Interview Questions and Answers on Python String
Prepare for your next interview with Important Interview Questions and Answers on Python String, covering key concepts, methods, and best practices.
1. What is String?
In Python, a string is a sequence of characters enclosed within single quotes (‘) or double quotes (“). Strings are used to represent text and can contain letters, numbers, symbols, and spaces.
# Single quotes
name = ‘John’
# Double quotes
greeting = “Hello, world!”
# Multiline string (using triple quotes)
message = “””This is a
multiline string.”””
Strings in Python are immutable, meaning that once a string is created, it cannot be changed. You can create new strings by concatenating, slicing, or modifying them, but the original string remains unchanged.
2. What is String manipulation?
String manipulation in Python refers to the process of modifying, analyzing, or handling strings in various ways. Python provides several built-in methods and operators that allow you to perform common operations such as slicing, concatenation, searching, replacing, and modifying strings. Since strings are immutable in Python, most string manipulation operations return a new string without modifying the original string.
3. What are String manipulation methods?
Python provides a wide range of string manipulation methods that allow you to perform various operations on strings.
The methods are:-
capitalize()
Capitalizes the first character of the string and makes the rest lowercase.
casefold()
Returns a casefolded copy of the string (for case-insensitive comparisons).
center(width, fillchar)
Centers the string within a given width and pads with fillchar.
count(substring)
Returns the number of occurrences of the substring.
encode(encoding)
Encodes the string using the specified encoding.
endswith(suffix)
Returns True if the string ends with the specified suffix.
expandtabs(tabsize)
Expands tab characters to spaces.
find(substring)
Returns the lowest index where the substring is found or -1 if not found.
format(*args, **kwargs)
Formats the string with placeholders.
index(substring)
Returns the index of the first occurrence of the substring, raises an exception if not found.
isalnum()
Returns True if all characters are alphanumeric.
isalpha()
Returns True if all characters are alphabetic.
isdecimal()
Returns True if all characters are decimal characters.
isdigit()
Returns True if all characters are digits.
isidentifier()
Returns True if the string is a valid identifier.
islower()
Returns True if all characters are lowercase.
isnumeric()
Returns True if all characters are numeric.
isprintable()
Returns True if all characters are printable.
isspace()
Returns True if the string contains only whitespace characters.
istitle()
Returns True if the string is in title case.
isupper()
Returns True if all characters are uppercase.
join(iterable)
Joins elements of an iterable (like a list) into a string, separated by the string.
ljust(width, fillchar)
Left-justifies the string within the specified width, padding with fillchar.
lower()
Converts the string to lowercase.
lstrip()
Removes leading whitespaces or specified characters from the string.
replace(old, new)
Replaces all occurrences of old with new.
rfind(substring)
Returns the highest index where the substring is found or -1 if not found.
rindex(substring)
Returns the highest index where the substring is found, raises an exception if not found.
removeprefix(prefix)
Removes the specified prefix if present.
removesuffix(suffix)
Removes the specified suffix if present.
rstrip()
Removes trailing whitespaces or specified characters from the string.
split(sep, maxsplit)
Splits the string into a list based on the separator sep.
splitlines()
Splits the string at line boundaries.
startswith(prefix)
Returns True if the string starts with the specified prefix.
strip()
Removes leading and trailing whitespaces or specified characters from the string.
swapcase()
Swaps the case of all characters in the string.
title()
Capitalizes the first character of each word in the string.
upper()
Converts the string to uppercase.
zfill(width)
Pads the string with zeros to reach the specified width.
isascii()
Returns True if all characters in the string are ASCII characters.
isdecimal()
Returns True if all characters in the string are decimal characters.
isnumeric()
Returns True if all characters in the string are numeric.
isxdigit()
Returns True if all characters in the string are hexadecimal digits.
4. What are the top 5 String manipulation methods used in Data analytics?
str.strip()
Purpose: Removes leading and trailing whitespaces or unwanted characters.
Use in Data Analytics: Often used to clean up data, especially when dealing with user input or raw data that has extra spaces or special characters at the beginning or end of strings.
str.replace(old, new)
Purpose: Replaces occurrences of a substring with another substring.
Use in Data Analytics: It’s vital for standardizing data (e.g., replacing missing values represented as ‘N/A’ with None or correcting inconsistent spelling or formatting).
str.split(sep, maxsplit)
Purpose: Splits a string into a list based on a separator.
Use in Data Analytics: This method is useful when extracting specific parts of data, like separating dates into day, month, and year or splitting addresses into street, city, and zip code.
str.lower() and str.upper()
Purpose: Converts a string to lowercase or uppercase.
Use in Data Analytics: Standardizing case (e.g., making all text lowercase) is essential for text comparison, searches, and grouping, ensuring consistency in textual data.
str.find(substring)
Purpose: Finds the lowest index of a substring within a string or returns -1 if the substring is not found.
Use in Data Analytics: This method is helpful for checking if a certain pattern or keyword exists in a dataset, such as identifying product codes or specific keywords in text data.
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