Unit 2: Strings and Functions
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Unit 2: Strings and Functions

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Questions and Answers

What does string padding involve?

  • Removing characters from a string
  • Adding characters to a string to reach a certain length (correct)
  • Reversing the characters in a string
  • Changing the string's data type

    • Which method is used to add spaces to the end of a string in Python?

  • str.ljust() (correct)
  • str.center()
  • str.rjust()
  • str.pad()

    • If you want to pad a string with dashes to the left until it reaches a length of 10, which method would you use?

  • text.rjust(10, '-') (correct)
  • text.center(10, '-')
  • text.pad(10, '-')
  • text.ljust(10, '-')

    • What will be the output of the following code? text = 'Python'
    padded_text = text.rjust(10, '-')
    print(padded_text)

    <p>----Python</p> Signup and view all the answers

    How does the str.center() method work?

    <p>It centers the string within a specified width</p> Signup and view all the answers

    What is the purpose of string splitting in Python?

    <p>To divide a string into multiple substrings based on a specified delimiter</p> Signup and view all the answers

    Which of the following correctly describes a property of strings in Python?

    <p>Strings can be concatenated and sliced to create new strings</p> Signup and view all the answers

    What will the following code output? text = 'Python'
    padded_text = text.center(10, '*')
    print(padded_text)

    <p><strong>Python</strong>*</p> Signup and view all the answers

    What is the primary purpose of the join() method in Python?

    <p>To concatenate strings with a specified delimiter</p> Signup and view all the answers

    What does the find() method return when the searched substring is not found?

    <p>-1</p> Signup and view all the answers

    Which method raises an error when a substring is not found?

    <p>index()</p> Signup and view all the answers

    What is required to use regular expressions in Python?

    <p>import re</p> Signup and view all the answers

    What will be the output of the following code: print('Hello'[::-1])?

    <p>olleH</p> Signup and view all the answers

    What does the len() function return when provided with the string 'Python'?

    <p>6</p> Signup and view all the answers

    What is obtained by the match.group(1) method in regex?

    <p>The first captured group</p> Signup and view all the answers

    How do you extract multiple groups from a regex match in Python?

    <p>Using match.group() with specific indices</p> Signup and view all the answers

    What regex pattern is used to capture age in the given example 'John Doe (42 years old)'?

    <p>( ext{(\d+) years old)</p> Signup and view all the answers

    What will be the output of re.search(r'xyz', 'Hello world')?

    <p>Match not found.</p> Signup and view all the answers

    What will be the output of print(len((1,2,3)))?

    <p>3</p> Signup and view all the answers

    What error is raised when trying to use len() on a boolean value?

    <p>TypeError</p> Signup and view all the answers

    What does the len() function return when applied to a dictionary with two key-value pairs?

    <p>2</p> Signup and view all the answers

    How can you access the last character of the string String1 = 'GeeksForGeeks' using negative indexing?

    <p>String1[-1]</p> Signup and view all the answers

    What is the maximum index that can be used to access the character in a string of length 10?

    <p>9</p> Signup and view all the answers

    What will be the output of print(len(range(1, 10)))?

    <p>9</p> Signup and view all the answers

    Which of the following correctly demonstrates the use of the len() function on a custom object?

    <p>len(Public(5))</p> Signup and view all the answers

    Which of the following operations is NOT a basic string operation?

    <p>Calculating square root of a string</p> Signup and view all the answers

    What will an IndexError signify when working with strings?

    <p>Accessing an index that is out of range</p> Signup and view all the answers

    When using indexing, which statement about accessing characters in a string is true?

    <p>Index must be an integer.</p> Signup and view all the answers

    What will be the output of the following code? text = 'Hello world, how are you today?'; words = text.split(); print(words)

    <p>['Hello', 'world,', 'how', 'are', 'you', 'today?']</p> Signup and view all the answers

    Which statement about the split() method is true?

    <p>It can use a specified separator when splitting strings.</p> Signup and view all the answers

    How does the maxsplit argument in the split() method function?

    <p>It specifies how many times the string can be split before stopping.</p> Signup and view all the answers

    What will be the output of the following code? price = 12.3456; formatted_price = f'The price is ${price:.2f}'; print(formatted_price)

    <p>The price is $12.35</p> Signup and view all the answers

    What will the output be when the function access_char_by_index is called with the string 'GeeksforGeeks ' and the index 4?

    <p>s</p> Signup and view all the answers

    What is the purpose of the strip() method in Python?

    <p>It removes leading and trailing characters from a string.</p> Signup and view all the answers

    What is needed to insert a string into another string using the insert_demo function?

    <p>Both the string to insert and the position to insert.</p> Signup and view all the answers

    What will be the result of executing this code? text = '!!!Hello, World!!!'; clean_text = text.strip('!'); print(clean_text)

    <p>'Hello, World'</p> Signup and view all the answers

    Which of the following correctly demonstrates string concatenation in Python?

    <p><code>result = string1 + string2</code></p> Signup and view all the answers

    In the replace_character_at_index function, how is the original string modified?

    <p>By converting it to a list of characters first.</p> Signup and view all the answers

    Which character would be removed from the string 'geeksforgeeks' when using the removeChar function with 'g' as the input?

    <p>g</p> Signup and view all the answers

    What will the output be if we run this code? delimiter = ' '; my_list = ['apple', 'banana', 'cherry']; result = delimiter.join(my_list); print(result)

    <p>apple banana cherry</p> Signup and view all the answers

    What is the main function of f-strings in Python?

    <p>To embed expressions inside string literals.</p> Signup and view all the answers

    What will the modified string be after executing insert_demo with 'GeeksGeeks ' as the original string, 'for' to insert, and 5 as the index?

    <p>GeeksforGeeks</p> Signup and view all the answers

    Which method can be used to replace specific characters within a string?

    <p>replace()</p> Signup and view all the answers

    What is the purpose of the character 'ch' in the context of modifying a string?

    <p>It is the character that replaces another character.</p> Signup and view all the answers

    If the original string is 'Geeks For Geeks' and we replace the character at index 6 with 'F', what will the modified string return?

    <p>Geeks For Geeks</p> Signup and view all the answers

    When concatenating strings, which method can be used to combine two strings in Python?

    <p>Using the plus (+) operator.</p> Signup and view all the answers

    Which combination of a character and its index would be appropriate for deleting a character from a string?

    <p>The character to delete and its position.</p> Signup and view all the answers

    If the character at index 3 of the string 'Programming' is replaced with 'X', what will the new string look like?

    <p>ProgrXmming</p> Signup and view all the answers

    Study Notes

    String Manipulation in Python

    • Strings are fundamental data structures in Python, represented as sequences of characters with single ('...') or double ("...") quotes.
    • They are immutable, meaning once created, they cannot be modified, but new strings can be created via concatenation or slicing.

    String Padding

    • String padding adds characters to the ends of a string to reach a specified length.
    • Use str.ljust(), str.rjust(), and str.center() for left, right, and center padding respectively.
    • Example of padding with ljust(): 
      text = "Python"
padded_text = text.ljust(10)
    • Padding can also use custom characters, such as dashes or asterisks.

    String Splitting

    • Splitting divides a string into substrings based on a specified delimiter using str.split().
    • By default, split() uses whitespace as the delimiter.
    • Specify custom delimiters like commas or dashes. Example: 
      text = "apple-banana-orange"
fruits = text.split('-')

    F-Strings for Formatting

    • Available in Python 3.6+, f-strings allow dynamic value embedding in strings.
    • Use {} braces to include variables. Example: 
      name = "Alice"
age = 30
greeting = f"Hello, my name is {name} and I'm {age}."

    Eliminating Unnecessary Characters

    • The strip() method removes leading or trailing characters.
    • For example: 
      text = "!!!Hello!!!"
clean_text = text.strip("!")

    Concatenating Strings

    • Strings can be concatenated using the + operator or the join() method for lists.
    • Example using +: 
      result = "Hello" + " " + "world"
    • Example using join(): 
      result = " ".join(["apple", "banana", "cherry"])

    Searching for Substrings

    • Use find() to locate substrings; returns -1 if not found, while index() raises an error.
    • Example: 
      title = 'How to search substrings'
print(title.find('search'))  # Returns index

    Regular Expressions for Complex Tasks

    • Regular expressions (regex) are used for pattern matching and string manipulation; import the re module.
    • Example of using regex to search: 
      import re
match = re.search("fox", "The quick brown fox")

    Reversing Strings

    • Strings can easily be reversed using slicing: 
      name = "Peter"
print(name[::-1])  # Outputs: reteP

    String Length with len() Function

    • The len() function returns the number of characters in a string.
    • Example: 
      print(len("Geeksforgeeks"))  # Outputs: 13

    Accessing Characters

    • Characters can be accessed via indexing, using positive and negative indices.
    • Example: 
      string = "GeeksForGeeks"
print(string[0])  # First character
print(string[-1]) # Last character

    Basic String Operations

    • Basic operations include accessing, inserting, modifying, and deleting characters, concatenation, and comparison.
    • Example of inserting a character: 
      modified_string = original_string[:k] + ch + original_string[k:]

    Deleting Characters

    • To delete a character, iterate through the string, avoiding the target character.
    • Example implementation: 
      def removeChar(s, c):
    return ''.join([char for char in s if char != c])

    Concatenating Strings

    • Strings can also be concatenated using + or through various methods for combining sequences easily.

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    Quiz Team

    Description

    Explore the fundamentals of string manipulation in Python. This quiz covers the essential techniques of creating, concatenating, and slicing strings, which are vital for every Python programmer. Understand the immutability of strings and become proficient in handling this core data structure.

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