Strings in Python Programming Language:
Strings are one of the most common and useful data types in Python. A string is considered a sequence or characters, in python enclosed using single quotes (”), double quotes (“”) or triple quotes (”’ ”’) into a standard Python code.
For example:
name = ‘Alice’
greeting = “Hello, world!”
quote = ”'”Learn a new programming language by writing programs in it.” – Lord Walles”’
Strings can be accessed by using indexing and slicing. Indexing means getting a single character from a string by using its position. Slicing means getting a substring from a string by using a range of positions.
For example:
name[0] # returns ‘A’
name[-1] # returns ‘e’
greeting[7:12] # returns ‘world’
quote[1:-1] # returns ‘”Learn a new programming language by writing programs in it.” – ‘Lord Walles’
Strings are immutable characters meaning that they cannot be changed after creating once. However, you can create new strings by using string methods or operators in the Python programming language. String methods are functions that perform some operation on a string and return a new string.
For example:
name.upper() # returns ‘ALICE’
greeting.replace(‘world’, ‘Python’) # returns ‘Hello, Python!’
quote.split() # returns [‘”The’, ‘only’, ‘way’, ‘to’, ‘learn’, ‘a’, ‘new’, ‘programming’, ‘language’, ‘is’, ‘by’, ‘writing’, ‘programs’, ‘in’, ‘it.”‘, ‘-‘, ‘Dennis’, ‘Ritchie’]
String operators are considered as symbols that can be used to combine or modify strings in Python.
For example:
name + ‘ is a programmer’ # returns ‘Alice is a programmer’
greeting * 3 # returns ‘Hello, world!Hello, world!Hello, world!’
‘Python’ in quote # returns True
Strings are very versatile and powerful data types that can be used for many purposes, such as storing and manipulating text data, representing names, addresses, and other types of data that can be represented as text.
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Interview Questions about Strings in Python
Strings are a fundamental data type in Python, and they are often used in interviews. Here are some of the most common questions asked about strings in Python interviews:
Here are some answers to the most frequently asked interview Strings questions:
How are strings written in Python?
Strings in Python are a sequence of characters. As mentioned earlier strings are enclosed in single or double quotes for general denotation.
For example, the following are strings:
“Hello, world!”
‘This is a string.’
How to declare a string in Python?
To declare a string in Python, you can use either single or double quotes. For example, the following are both valid ways to declare a string:
For example:
str1 = “Hello, world!”
str2 = ‘This is a string.’
How can characters be accessed within a String through Python program?
To access characters in a string in Python, you can use the index operator. The index operator is a number that indicates the position of the character in the string. For example, the following code will print the first character in the string str1:
For example:
print(str1[0])
What are the procedures for changing the case of a string in Python?
To change the case of a string in Python, you can use the upper() and lower() methods. The upper() method will convert all of the characters in the string to uppercase. The lower() method will convert all of the characters in the string to lowercase. For example, the following code will print the string str1 in uppercase:
For example:
print(str1.upper())
How can we remove spaces within a string sequence?
To remove spaces from a string in Python, you can use the strip() method. The strip() method will remove all of the leading and trailing spaces from the string. For example, the following code will print the string str2 without any leading or trailing spaces:
For example:
print(str2.strip())
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How can a string be split into a list in Python program?
To split a string into a list in Python, you can use the split() method. The split() method will split the string into a list of substrings, based on the delimiter. For example, the following code will split the string str3 into a list of substrings, based on the space character:
For example:
str3 = “This is a string.”
print(str3.split())
How to join a list into a string in Python?
To join a list into a string in Python, you can use the join() method. The join() method will join a list of strings into a single string, using the delimiter as the separator. For example, the following code will join the list list1 into a single string, using the comma as the separator:
For example:
list1 = [“This”, “is”, “a”, “list”]
print(“, “.join(list1))
How to confirm whether a string contains a substring within itself?
In order to ensure whether a string contains any substring within it, programmers can use the in operator function. If the substring is found within a string the operator will return True value whereas False is returned when not found. with any variable name which has value “Harish”:For example, the following code will check if the string str1 contains the substring “Hello”.
For example:
print(“Hello” in str1)
How to replace a substring in a string in Python?
To replace a substring in a string in Python, you can use the replace() method. The replace() method will replace all occurrences of the old substring with the new substring. For example, the following code will replace the substring “Hello” with the substring “Goodbye” in the string str1:
For example:
str1 = “Hello, world!”
print(str1.replace(“Hello”, “Goodbye”))
How to format a string in Python?
To format a string in Python, you can use the format() method. The format() method allows you to insert variables and expressions into a string. For example, the following code will format the string “Hello, {name}!” with any variable name which has value “Harish”::
For example:
name = “Harish”
print(“Hello, {name}!”.format(name=name))
How would you confirm that 2 strings have a similar identity?
To confirm a similar identity the operator will return True if 2 names point to the same location in Python memory.
For example:
animals = [‘python’,’gopher’]
more_animals = animals
print(animals == more_animals) #=> True
print(animals is more_animals) #=> True
even_more_animals = [‘python’,’gopher’]
print(animals == even_more_animals) #=> True
print(animals is even_more_animals) #=> False
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How would you check if a string begins with a capital letter for every word?
The istitle() function checks if each and every word is capitalized or not.
For example:
print( ‘The Hilton’.istitle() ) #=> True
print( ‘The dog’.istitle() ) #=> False
print( ‘sticky rice’.istitle() ) #=> False
How to check if any string contains a specific substring in it?
The in operator of Python will return True if a string contains a substring in it.
For example:
print( ‘plane’ in ‘Fastest plane in the world’ ) #=> True
print( ‘car’ in ‘Fastest plane in the world’ ) #=> False
How can you count the total number of characters in any given string?
The len() operator can be used to determine the length of a string.
For example:
len(‘He is first president of this organization.’) #=> 19
How to capitalize only the first character of a string?
Use the capitalize() function to convert the first character in a string.
For example:
‘florida dolphins’.capitalize() #=> ‘Florida dolphins’
How can you check if any string contains numbers only?
The isnumeric() function can be used to check this.
If isnumeric() returns True we can consider that all characters are numeric.
For example:
‘80000’.isnumeric() #=> True
Can an integer be added within a string in Python?
In some languages this can be done but Python will show a TypeError if any integer is added within the string command.
For example:
‘Ten’ + 10 #=> TypeError
How can you join multiple strings into a single string which can then be delimited by hyphens?
Python’s join() function can help you join characters in a list with a given character inserted between every element.
For example:
‘-‘.join([‘a’,’b’,’c’])
#=> ‘a-b-c’
How to make an uppercase or lowercase an entire string?
The codes upper() and lower() can be used to return strings in all upper and lower cases.
For example:
sentence = ‘The Cat in the Hat’
sentence.upper() #=> ‘THE CAT IN THE HAT’
sentence.lower() #=> ‘the cat in the hat’
When would you use splitlines() in strings for Python?
splitlines() splits a string on line breaks and creates new strings.
For emample:
sentence = “The night was stormy\nHouse was cracking\nThe wind was blowing.”
sentence.splitlines()
#=> [‘The night was stormy’, ‘House was cracking’, ‘The wind was blowing.’]
Conclusion:
We hope you find this blog useful and the questions covered in it helpful for your Python job interviews. Please feel free to contact SevenMentor Institute for any Python Strings-related questions. We also have a Python Course at SevenMentor which can help you learn more about this topic and get the best job in the IT sector after training.
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