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)

----Python (A) Signup and view all the answers

How does the str.center() method work?

It centers the string within a specified width (C) Signup and view all the answers

What is the purpose of string splitting in Python?

To divide a string into multiple substrings based on a specified delimiter (C) Signup and view all the answers

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

Strings can be concatenated and sliced to create new strings (B) Signup and view all the answers

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

Python* (B) Signup and view all the answers

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

To concatenate strings with a specified delimiter (A) Signup and view all the answers

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

-1 (B) Signup and view all the answers

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

index() (D) Signup and view all the answers

What is required to use regular expressions in Python?

import re (B) Signup and view all the answers

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

olleH (C) Signup and view all the answers

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

6 (A), 6.0 (B) Signup and view all the answers

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

The first captured group (D) Signup and view all the answers

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

Using match.group() with specific indices (B) Signup and view all the answers

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

( ext{(\d+) years old) (D) Signup and view all the answers

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

Match not found. (D) Signup and view all the answers

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

3 (B) Signup and view all the answers

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

TypeError (C) Signup and view all the answers

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

2 (D) Signup and view all the answers

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

String1[-1] (C) 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?

9 (B) Signup and view all the answers

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

9 (B) Signup and view all the answers

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

len(Public(5)) (A) Signup and view all the answers

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

Calculating square root of a string (A) Signup and view all the answers

What will an IndexError signify when working with strings?

Accessing an index that is out of range (A) Signup and view all the answers

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

Index must be an integer. (D) 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)`

['Hello', 'world,', 'how', 'are', 'you', 'today?'] (C) Signup and view all the answers

Which statement about the `split()` method is true?

It can use a specified separator when splitting strings. (C) Signup and view all the answers

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

It specifies how many times the string can be split before stopping. (A) 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)`

The price is $12.35 (C) 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?

s (A) Signup and view all the answers

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

It removes leading and trailing characters from a string. (B) Signup and view all the answers

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

Both the string to insert and the position to insert. (B) 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)`

'Hello, World' (B), 'Hello, World' (C) Signup and view all the answers

Which of the following correctly demonstrates string concatenation in Python?

<code>result = string1 + string2</code> (C) Signup and view all the answers

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

By converting it to a list of characters first. (A) 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?

g (C) 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)`

apple banana cherry (C) Signup and view all the answers

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

To embed expressions inside string literals. (A) 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?

GeeksforGeeks (D) Signup and view all the answers

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

replace() (B) Signup and view all the answers

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

It is the character that replaces another character. (C) 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?

Geeks For Geeks (C) Signup and view all the answers

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

Using the plus (+) operator. (C) Signup and view all the answers

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

The character to delete and its position. (B) 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?

ProgrXmming (C) 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.

Studying That Suits You

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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.

Unit 2: Strings and Functions

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Podcast

Questions and Answers

What does string padding involve?

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

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

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

How does the str.center() method work?

What is the purpose of string splitting in Python?

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

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

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

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

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

What is required to use regular expressions in Python?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

What will an IndexError signify when working with strings?

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

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

Which statement about the split() method is true?

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

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

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

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

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

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

Which of the following correctly demonstrates string concatenation in Python?

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

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

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

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

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

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

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

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

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

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

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

Study Notes

String Manipulation in Python

String Padding

String Splitting

F-Strings for Formatting

Eliminating Unnecessary Characters

Concatenating Strings

Searching for Substrings

Regular Expressions for Complex Tasks

Reversing Strings

String Length with len() Function

Accessing Characters

Basic String Operations

Deleting Characters

Concatenating Strings

Studying That Suits You

Description

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Python String Methods Quiz

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

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

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

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

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

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

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

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

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

Which statement about the `split()` method is true?

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

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

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

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

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