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Questions and Answers
What is the index of the first element in a Python list?
What is the index of the first element in a Python list?
What does the negative index -2 represent in a list?
What does the negative index -2 represent in a list?
Which of the following will correctly return the items from the third to the fifth position in the list?
Which of the following will correctly return the items from the third to the fifth position in the list?
Which of the following statements about Python lists is true?
Which of the following statements about Python lists is true?
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What will be the output of print(thislist[-4:-1]) for thislist = ['apple', 'banana', 'cherry', 'orange', 'kiwi', 'melon', 'mango']?
What will be the output of print(thislist[-4:-1]) for thislist = ['apple', 'banana', 'cherry', 'orange', 'kiwi', 'melon', 'mango']?
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How can you access the third item in the list named thislist?
How can you access the third item in the list named thislist?
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Which expression correctly checks if 'banana' is in the list?
Which expression correctly checks if 'banana' is in the list?
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Which built-in Python function is NOT applicable to sequences?
Which built-in Python function is NOT applicable to sequences?
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What is a key difference between Python lists and arrays in C/C++/Java?
What is a key difference between Python lists and arrays in C/C++/Java?
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What will be printed by print(thislist[:4]) if thislist = ['apple', 'banana', 'cherry', 'orange', 'kiwi']?
What will be printed by print(thislist[:4]) if thislist = ['apple', 'banana', 'cherry', 'orange', 'kiwi']?
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Which operation is NOT supported by Python sequences?
Which operation is NOT supported by Python sequences?
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If list1 = ['Rohan', 'Physics', 21, 69.75], what does list1[0] return?
If list1 = ['Rohan', 'Physics', 21, 69.75], what does list1[0] return?
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What is the effect of leaving out the end value in slicing, like thislist[2:]?
What is the effect of leaving out the end value in slicing, like thislist[2:]?
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What does the following code snippet print? list1 = ['a', 'b', 'c']; print(list1[1])
What does the following code snippet print? list1 = ['a', 'b', 'c']; print(list1[1])
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What will happen if you attempt to access an index that is out of range in a Python list?
What will happen if you attempt to access an index that is out of range in a Python list?
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For a list that contains integers, what does the expression thislist[-3] return if thislist = [1, 2, 3, 4, 5]?
For a list that contains integers, what does the expression thislist[-3] return if thislist = [1, 2, 3, 4, 5]?
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What does list1[1:3] return if list1 = ['a', 'b', 'c', 'd']?
What does list1[1:3] return if list1 = ['a', 'b', 'c', 'd']?
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Which method would you use to remove a specific element from a list?
Which method would you use to remove a specific element from a list?
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What will be the output of this code: list = [1, 2, 3]; list.pop(); print(list)?
What will be the output of this code: list = [1, 2, 3]; list.pop(); print(list)?
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How can you determine the number of elements in a list?
How can you determine the number of elements in a list?
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What is the result of the code list = [1, 2, 5, 6]; max(list)?
What is the result of the code list = [1, 2, 5, 6]; max(list)?
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What will be the output of l1 = [1, 2, 3]; l2 = [4, 5]; print(l1 + l2)?
What will be the output of l1 = [1, 2, 3]; l2 = [4, 5]; print(l1 + l2)?
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To iterate through the elements of a list, which construct is used?
To iterate through the elements of a list, which construct is used?
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What will the following code print? list = [1, 2, 3]; list[0] = 'New'; print(list)
What will the following code print? list = [1, 2, 3]; list[0] = 'New'; print(list)
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Which of the following statements is true about Python lists?
Which of the following statements is true about Python lists?
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What will be the output of the following code: print(list1[1:]) if list1 = ['a', 'b', 'c', 'd']?
What will be the output of the following code: print(list1[1:]) if list1 = ['a', 'b', 'c', 'd']?
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What does the negative index -1 represent in a Python list?
What does the negative index -1 represent in a Python list?
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Which method would you use to add an element at a specific position in a Python list?
Which method would you use to add an element at a specific position in a Python list?
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What will the following code print: list = ['Student', 'Teacher', 'Parent']; print(list[2:5])?
What will the following code print: list = ['Student', 'Teacher', 'Parent']; print(list[2:5])?
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What is the correct output when using the sort() method on the list ['Student', 'Teacher', 'Parent', 'Friend']?
What is the correct output when using the sort() method on the list ['Student', 'Teacher', 'Parent', 'Friend']?
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If you want to combine a list with another iterable in Python, which method should you use?
If you want to combine a list with another iterable in Python, which method should you use?
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When accessing elements with a range in Python list slicing, which statement is correct?
When accessing elements with a range in Python list slicing, which statement is correct?
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Which code snippet accurately demonstrates using negative indexing in Python?
Which code snippet accurately demonstrates using negative indexing in Python?
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What will the output be for the code: list = ['Python', 'Java', 'C++']; list.insert(1, 'JavaScript'); print(list)?
What will the output be for the code: list = ['Python', 'Java', 'C++']; list.insert(1, 'JavaScript'); print(list)?
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If you want to update the first element of a list named 'list' that holds elements ['a', 'b', 'c'], which of the following is correct?
If you want to update the first element of a list named 'list' that holds elements ['a', 'b', 'c'], which of the following is correct?
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What does the pop() method return when called on a list?
What does the pop() method return when called on a list?
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Which of the following operations allows you to create a new tuple from two existing tuples?
Which of the following operations allows you to create a new tuple from two existing tuples?
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What will be the output of my_list.count(3) if my_list = [1, 2, 3, 4, 3]?
What will be the output of my_list.count(3) if my_list = [1, 2, 3, 4, 3]?
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What will happen if you try to access an index that does not exist in a tuple?
What will happen if you try to access an index that does not exist in a tuple?
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Which method would you use to sort the elements of a list in ascending order?
Which method would you use to sort the elements of a list in ascending order?
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Which statement correctly describes tuples in Python?
Which statement correctly describes tuples in Python?
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How do you explicitly delete a tuple in Python?
How do you explicitly delete a tuple in Python?
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What does my_list.index(3) return if my_list = [1, 2, 3, 4, 3]?
What does my_list.index(3) return if my_list = [1, 2, 3, 4, 3]?
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What is the output of print(my_list) after executing my_list.reverse() if my_list = [1, 2, 3, 4]?
What is the output of print(my_list) after executing my_list.reverse() if my_list = [1, 2, 3, 4]?
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What is the key difference between a list and a tuple in Python?
What is the key difference between a list and a tuple in Python?
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What type of data can be used as keys in a Python dictionary?
What type of data can be used as keys in a Python dictionary?
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What will happen if you try to use a list as a key in a dictionary?
What will happen if you try to use a list as a key in a dictionary?
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Which of the following is a valid way to define a Python dictionary?
Which of the following is a valid way to define a Python dictionary?
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How are key-value pairs in a dictionary formatted?
How are key-value pairs in a dictionary formatted?
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What will be the output of the following code? d1 = {'a': 1, 'b': 2, 'a': 3}; print(d1)
What will be the output of the following code? d1 = {'a': 1, 'b': 2, 'a': 3}; print(d1)
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Which of the following statements is true regarding dictionary values?
Which of the following statements is true regarding dictionary values?
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What is the correct syntax for creating an empty dictionary in Python?
What is the correct syntax for creating an empty dictionary in Python?
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In Python dictionaries, how do you access values associated with keys?
In Python dictionaries, how do you access values associated with keys?
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What function would you use to find the number of elements in a list?
What function would you use to find the number of elements in a list?
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Which method would you use to add an element to the end of a list?
Which method would you use to add an element to the end of a list?
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How can a tuple with a single element be correctly defined?
How can a tuple with a single element be correctly defined?
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What will occur if you attempt to access an index in a tuple that exceeds its length?
What will occur if you attempt to access an index in a tuple that exceeds its length?
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How can you access the last element of a list named my_list?
How can you access the last element of a list named my_list?
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What is the output of trying to access tuple_[1.0] from tuple_ = ('Python', 'Tuple', 'Ordered', 'Collection')?
What is the output of trying to access tuple_[1.0] from tuple_ = ('Python', 'Tuple', 'Ordered', 'Collection')?
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What will the result of the operation my_list.remove(4) be if my_list = [1, 2, 3, 4, 4]?
What will the result of the operation my_list.remove(4) be if my_list = [1, 2, 3, 4, 4]?
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How does negative indexing work in Python tuples?
How does negative indexing work in Python tuples?
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What does the pop() method return if called without an index on a list named my_list?
What does the pop() method return if called without an index on a list named my_list?
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Which code line correctly prints elements between the 1st and 3rd indices of a tuple?
Which code line correctly prints elements between the 1st and 3rd indices of a tuple?
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Which function is used to get the highest value in a list?
Which function is used to get the highest value in a list?
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What will be displayed as a result of the following operation: my_list = [1, 2, 3]; my_list.extend([4, 5])?
What will be displayed as a result of the following operation: my_list = [1, 2, 3]; my_list.extend([4, 5])?
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What will be printed by the code print(tuple_[:-4]) if tuple_ = ('Python', 'Tuple', 'Ordered', 'Immutable', 'Collection', 'Objects')?
What will be printed by the code print(tuple_[:-4]) if tuple_ = ('Python', 'Tuple', 'Ordered', 'Immutable', 'Collection', 'Objects')?
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Which method is used to reverse the order of elements in a list?
Which method is used to reverse the order of elements in a list?
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What will happen if you attempt to create a tuple without parentheses but include a trailing comma, such as single_tuple = 'Tuple',?
What will happen if you attempt to create a tuple without parentheses but include a trailing comma, such as single_tuple = 'Tuple',?
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Which of the following statements is true regarding tuple slicing?
Which of the following statements is true regarding tuple slicing?
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What output will the following code produce? my_list = [1, 2, 3]; my_list.insert(1, 'a')
What output will the following code produce? my_list = [1, 2, 3]; my_list.insert(1, 'a')
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What will my_list look like after executing the code my_list = [1, 2, 3]; del my_list[0]?
What will my_list look like after executing the code my_list = [1, 2, 3]; del my_list[0]?
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What type of error will be raised if a non-integer is used as an index in a tuple?
What type of error will be raised if a non-integer is used as an index in a tuple?
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What indexing error is shown when trying to access more elements than are present in a tuple?
What indexing error is shown when trying to access more elements than are present in a tuple?
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What happens when you attempt to change an immutable tuple directly?
What happens when you attempt to change an immutable tuple directly?
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Which operator would you use to combine two tuples into a single tuple?
Which operator would you use to combine two tuples into a single tuple?
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What does the * operator do when applied to a tuple?
What does the * operator do when applied to a tuple?
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Which function can be used to get the number of elements in a tuple?
Which function can be used to get the number of elements in a tuple?
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Can mutable objects be changed when they are contained within a tuple?
Can mutable objects be changed when they are contained within a tuple?
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What will be the output of the expression (2, 5) * 3?
What will be the output of the expression (2, 5) * 3?
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Which statement correctly describes how tuples handle accidental modifications?
Which statement correctly describes how tuples handle accidental modifications?
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Which function can be used to determine the maximum value in a tuple?
Which function can be used to determine the maximum value in a tuple?
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What is true about the cmp() function when comparing two tuples?
What is true about the cmp() function when comparing two tuples?
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Why can tuples be used as dictionary keys while lists cannot?
Why can tuples be used as dictionary keys while lists cannot?
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What is the result of the expression (1, 2, 3) + (4, 5, 6)?
What is the result of the expression (1, 2, 3) + (4, 5, 6)?
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What does the expression ('Hi!',) * 4 return?
What does the expression ('Hi!',) * 4 return?
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What will be the result when attempting to access a key that does not exist in a Python dictionary?
What will be the result when attempting to access a key that does not exist in a Python dictionary?
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What will the result of 3 in (1, 2, 3) evaluate to?
What will the result of 3 in (1, 2, 3) evaluate to?
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Which method would correctly add a new key-value pair to an existing dictionary?
Which method would correctly add a new key-value pair to an existing dictionary?
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What will be the output of L[1:] if L = ('spam', 'Spam', 'SPAM!')?
What will be the output of L[1:] if L = ('spam', 'Spam', 'SPAM!')?
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What will happen if you try to delete a key that does not exist in a Python dictionary?
What will happen if you try to delete a key that does not exist in a Python dictionary?
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Which function is used to find the minimum value in a tuple?
Which function is used to find the minimum value in a tuple?
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What types can be used as keys in a Python dictionary?
What types can be used as keys in a Python dictionary?
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What is a key characteristic of tuples compared to lists?
What is a key characteristic of tuples compared to lists?
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After executing the following code, what will be the output? dict = {'Name': 'Zara', 'Age': 7, 'Name': 'Manni'}. What is dict['Name']?
After executing the following code, what will be the output? dict = {'Name': 'Zara', 'Age': 7, 'Name': 'Manni'}. What is dict['Name']?
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What will be the output of the line print(type(tuple_)) if tuple_ = 4, 5.7, 'Tuples', ['Python', 'Tuples']?
What will be the output of the line print(type(tuple_)) if tuple_ = 4, 5.7, 'Tuples', ['Python', 'Tuples']?
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What does the built-in function len(tuple) return?
What does the built-in function len(tuple) return?
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What does the 'clear()' method do when called on a dictionary?
What does the 'clear()' method do when called on a dictionary?
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What will the code produce when executing 'del dict' on a defined dictionary?
What will the code produce when executing 'del dict' on a defined dictionary?
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What represents a nested tuple?
What represents a nested tuple?
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What will happen if a comma is omitted from a single-item tuple like (5)?
What will happen if a comma is omitted from a single-item tuple like (5)?
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Which of the following statements about dictionary keys is true?
Which of the following statements about dictionary keys is true?
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If a dictionary is initialized as dict = {['Name']: 'Zara', 'Age': 7}, what will happen?
If a dictionary is initialized as dict = {['Name']: 'Zara', 'Age': 7}, what will happen?
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What will be printed after executing these commands: dict = {'Name': 'Zara', 'Age': 7}; del dict['Name']; print(dict)?
What will be printed after executing these commands: dict = {'Name': 'Zara', 'Age': 7}; del dict['Name']; print(dict)?
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What happens when you use the keyword del on a tuple variable?
What happens when you use the keyword del on a tuple variable?
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Which operation can be performed on tuples?
Which operation can be performed on tuples?
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What does the count() method return when applied to a tuple?
What does the count() method return when applied to a tuple?
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Which of the following statements about the index() method in tuples is true?
Which of the following statements about the index() method in tuples is true?
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How can you check for the existence of an element in a tuple?
How can you check for the existence of an element in a tuple?
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Given the output of count() method, what does the output 'Count of 2 in T1 is: 5' indicate?
Given the output of count() method, what does the output 'Count of 2 in T1 is: 5' indicate?
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What is the tuple after the operation tuple_ = tuple_ * 3 when tuple_ originally is ('Python', 'Tuples')?
What is the tuple after the operation tuple_ = tuple_ * 3 when tuple_ originally is ('Python', 'Tuples')?
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What will be printed if you check membership using 'print('Tuple' in tuple_)' where tuple_ is ('Python', 'Tuple', 'Ordered')?
What will be printed if you check membership using 'print('Tuple' in tuple_)' where tuple_ is ('Python', 'Tuple', 'Ordered')?
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What output is expected from the print statement: print('Items' in tuple_) when tuple_ is defined as ('Python', 'Tuple', 'Ordered')?
What output is expected from the print statement: print('Items' in tuple_) when tuple_ is defined as ('Python', 'Tuple', 'Ordered')?
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What will the output be when trying to access tuple_ after executing del tuple_ if tuple_ was initially ('Python', 'Tuple')?
What will the output be when trying to access tuple_ after executing del tuple_ if tuple_ was initially ('Python', 'Tuple')?
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What will be the output of the command print(Employee['Name']) if Employee is defined as Employee = {'Name': 'Dev', 'Age': 20, 'salary': 45000, 'Company': 'WIPRO'}?
What will be the output of the command print(Employee['Name']) if Employee is defined as Employee = {'Name': 'Dev', 'Age': 20, 'salary': 45000, 'Company': 'WIPRO'}?
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Which statement correctly describes how to update an existing value in a dictionary?
Which statement correctly describes how to update an existing value in a dictionary?
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What is the result of executing d3 = d1 | d2 in Python?
What is the result of executing d3 = d1 | d2 in Python?
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What will happen if you attempt to access a key that does not exist in a dictionary using indexing?
What will happen if you attempt to access a key that does not exist in a dictionary using indexing?
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What does the method dict.copy() return?
What does the method dict.copy() return?
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What is the output of print(Dict) after executing the code Dict = dict([(4, 'Rinku'), (2, 'Singh')])?
What is the output of print(Dict) after executing the code Dict = dict([(4, 'Rinku'), (2, 'Singh')])?
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What will the output be of executing d1.clear()?
What will the output be of executing d1.clear()?
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How are dictionary keys defined in Python?
How are dictionary keys defined in Python?
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What will be printed after executing print(Dict) if Dict is initialized as Dict = {} and then three items are added?
What will be printed after executing print(Dict) if Dict is initialized as Dict = {} and then three items are added?
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Which statement about dictionary keys in Python is true?
Which statement about dictionary keys in Python is true?
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What method can be used to safely access a value in a dictionary without raising an error for a nonexistent key?
What method can be used to safely access a value in a dictionary without raising an error for a nonexistent key?
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What will be the output of print(d1.get('x', 10)) if 'x' is not a key in d1?
What will be the output of print(d1.get('x', 10)) if 'x' is not a key in d1?
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What will be the output of the command print(Dict['Emp_ages']) if Dict contains the key 'Emp_ages' with the value (20, 33, 24)?
What will be the output of the command print(Dict['Emp_ages']) if Dict contains the key 'Emp_ages' with the value (20, 33, 24)?
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Which method can be used to create a new dictionary from an existing one with only specific keys?
Which method can be used to create a new dictionary from an existing one with only specific keys?
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Which of the following operations is NOT permitted on dictionary keys?
Which of the following operations is NOT permitted on dictionary keys?
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What is the output of executing dict1.update(dict2) if dict1 = {'a': 1} and dict2 = {'a': 2, 'b': 3}?
What is the output of executing dict1.update(dict2) if dict1 = {'a': 1} and dict2 = {'a': 2, 'b': 3}?
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What will the expression len(d1) return if d1 = {'a': 1, 'b': 2, 'c': 3}?
What will the expression len(d1) return if d1 = {'a': 1, 'b': 2, 'c': 3}?
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Which of the following correctly describes a Python dictionary?
Which of the following correctly describes a Python dictionary?
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What type of values can a dictionary hold in Python?
What type of values can a dictionary hold in Python?
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Study Notes
Data Structures in Python: Lists and Tuples
Lists Introduction
- The basic data structure in Python is the sequence, where each element is assigned an index starting from 0.
- Python includes six built-in sequence types; the most common are lists and tuples.
- Operations applicable to all sequence types: indexing, slicing, adding, multiplying, and membership checking.
- Python has functions to determine sequence length, largest, and smallest elements.
Python Lists
- A list is a sequence of comma-separated items defined in square brackets, e.g.,
list1 = ["Rohan", "Physics", 21, 69.75]. - Lists can contain mixed data types and are ordered, mutable collections.
- Lists are similar to arrays in C/C++/Java but can hold different data types in Python.
- Items can be accessed, modified, added, or removed, and duplicates are allowed.
Accessing Lists
- List items can be accessed using their index with zero-based numbering.
- Negative indexing allows access from the end, e.g., -1 for the last item.
- Slicing can return a range of items, e.g.,
thislist[2:5]gives the third to fifth items. - The
inkeyword checks for item presence in the list.
List Operations
- Lists support comprehensive operations:
-
Accessing Elements: Using indices for direct access, e.g.,
list[0]for the first item. -
Adding Elements: Use
append(adds to end) andinsert(adds at specific index). -
Sorting:
sort()method sorts lists either in ascending or descending order. - Updating Elements: Modify items directly by their index.
-
Removing Elements:
remove()deletes by item value;pop()removes last or specified item. -
Length:
len()provides the count of elements in the list. -
Maximum/Minimum:
max()andmin()return largest and smallest items, respectively. -
Concatenation: Use the
+operator to join lists together. - Iteration: Loop through items using a for-loop.
-
Accessing Elements: Using indices for direct access, e.g.,
Working with Lists
- Lists are mutable and can be manipulated by adding, removing, or modifying items.
- Creation uses square brackets; access items through their indices or slices.
- Methods like
clear()(removes all elements) andcopy()(creates a copy) enhance list functionality.
Tuple Introduction
- Tuples are similar to lists but are defined in parentheses, e.g.,
tup1 = ("Rohan", "Physics", 21, 69.75). - They can also include mixed data types and are indexed starting from 0.
- Unlike lists, tuples are immutable: their content cannot be modified or removed.
- An empty tuple is instantiated with
();a single-value tuple requires a trailing comma, e.g.,(50,);.
Accessing Values in Tuples
- Access values in tuples using indices or slicing similar to lists, e.g.,
tup[1]. - Create new tuples via concatenation of existing tuples as tuples cannot be modified in place.
Tuple Operations
- Tuples support concatenation using the
+operator and repetition using the*operator. - Membership testing with "in" and "not in" is applicable to tuples as well.
These notes summarize the principles of handling lists and tuples in Python, their accessibility, mutability comparisons, and available operations and methods.### Python Tuples
- A tuple is an immutable, ordered collection of elements, created by enclosing elements in parentheses and separating them with commas.
- Example of tuple creation:
tuple1 = (1, 2, 3). - Tuples can contain diverse data types, including other tuples, lists, strings, or dictionaries.
- Single-element tuples must have a comma, e.g.,
single_tuple = (1,).
Tuple Operations
-
Concatenation: Combine tuples using the
+operator, e.g.,(1, 2) + (3, 4)results in(1, 2, 3, 4). -
Repetition: Repeat tuple elements using the
*operator, e.g.,('a',) * 3results in('a', 'a', 'a'). -
Membership Testing: Use the
inkeyword to check if an element exists in a tuple.
Accessing Elements
-
Indexing: Access elements using indices starting from 0. Example:
tuple1[0]accesses the first element. -
Negative Indexing: Count from the end using negative indices, e.g.,
tuple1[-1]accesses the last element. -
Slicing: Extract subsections of a tuple using the colon
:operator. Example:tuple1[1:3]returns a slice.
Built-in Functions for Tuples
-
len(tuple): Returns the number of elements in a tuple. -
max(tuple): Finds the maximum value in a tuple. -
min(tuple): Finds the minimum value in a tuple. -
tuple(seq): Converts a sequence (like a list) into a tuple.
Tuples vs Lists
- Tuples are immutable; their contents cannot be changed after creation, while lists are mutable and can be modified.
- Tuples are faster than lists and can be used as keys in dictionaries.
Creating and Deleting Tuples
- Creating a tuple can be done without parentheses, e.g.,
tuple_ = 1, 2, 3. - Use the
delstatement to delete a tuple entirely, as individual elements cannot be deleted.
Tuple Methods
-
count()Method: Returns the number of occurrences of a specified element in the tuple. -
index()Method: Returns the index of the first occurrence of a specified element in the tuple.
Iterating Through Tuples
- Use a
forloop to iterate over each element in the tuple.
Dictionaries in Python
- A dictionary is a mutable collection of key-value pairs, enclosed in curly braces
{}. - Keys must be unique and immutable types (strings, numbers, tuples), while values can be of any data type.
Accessing and Modifying Dictionaries
- Access values using square brackets and the corresponding key, e.g.,
dict['Name']. - Update existing keys or add new key-value pairs easily, e.g.,
dict['Age'] = 8. - Use
delto remove specific key-value pairs or entire dictionaries.
Example of a Dictionary
- Example of a simple dictionary:
dict = {'Name': 'Zara', 'Age': 7}.
Key Features of Dictionaries
- Supports fast access to elements.
- Allows dynamic resizing.
- Can store complex data structures within values (like lists or other dictionaries).
Error Handling
- Accessing a nonexistent key in a dictionary raises a
KeyError. - Check if a key exists in a dictionary using
into avoid errors.
Conclusion
- Mastery of tuples and dictionaries is essential for efficient data management in Python programming.### Python Dictionaries Overview
- Python dictionaries store data as key-value pairs, allowing for efficient data retrieval and manipulation.
- Dictionaries are mutable, meaning their contents can be changed after creation.
- Keys must be unique and immutable; suitable types include strings, numbers, and tuples.
- Values can be of any type, such as integers, lists, and even other dictionaries.
Creating Dictionaries
- Curly brackets {} are commonly used to create a dictionary:
Dict = {"Name": "Gayle", "Age": 25}. - The built-in
dict()function can also create dictionaries, either empty or with initial key-value pairs.
Accessing and Modifying Values
- Access values using keys with the syntax
dict[key]. - Use the
get()method to retrieve values, which provides a default if the key is not found. - Update values or add new key-value pairs using assignment, e.g.,
dict[key] = value, or theupdate()method for batch additions.
Dictionary Operations
- Removing a key can be done using
del dict[key]or theclear()method to empty the dictionary entirely. - The union operator
|combines two dictionaries without affecting the originals, creating a new dictionary.
Dictionary Methods
-
dict.clear(): Removes all entries. -
dict.copy(): Returns a shallow copy of the dictionary. -
dict.fromkeys(sequence, value): Creates a new dictionary with specified keys and a default value. -
dict.items(): Returns a list of (key, value) tuple pairs. -
dict.keys(): Returns a list of keys in the dictionary. -
dict.values(): Returns a list of values in the dictionary.
Built-in Functions
-
len(dict): Returns the number of key-value pairs in the dictionary. -
str(dict): Provides a string representation of the dictionary. -
type(variable): Determines the type of the passed variable, indicating if it's a dictionary.
Key Characteristics
- No duplicates allowed; if duplicate keys are assigned, the last assigned value takes precedence.
- Example of handling duplicates:
dict = {'Name': 'Zara', 'Age': 7, 'Name': 'Manni'}results indict['Name']returning 'Manni'. - Keys must be immutable types - lists cannot be used as keys.
Deleting Elements
- Use the
delkeyword to remove specific key-value pairs ordict.clear()to remove all entries.
Example Code Demonstration
- Simple dictionary creation and manipulation:
Employee = {"Name": "Johnny", "Age": 32, "salary": 26000, "Company": "^TCS"} print(Employee) del Employee['Name'] print(Employee) Employee.clear() print(Employee) - Demonstrates how to handle updates and add new employees through user input.
Conclusion
- Python dictionaries are crucial for dynamic data storage and efficient access, closely resembling real-world data associations.
- They facilitate easy data management through their flexible structure, methods, and support for various operations.
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Description
Explore the fundamental concepts of data structures in Python, focusing on lists as a primary sequence type. This quiz covers indexing, slicing, and various operations associated with lists. Understand how lists facilitate data management in Python programming.
