Initialization

str1 = 'Text enclosed with single quotes.' 

str2 = "Text enclosed with double quotes."

 

Access

  • The in-operator can be used to check a substring exists in a string.
print("single" in str1)   # output: True
  • The subscript-operator can be used for accessing a character using the correspoding index. IndexError-exception will be thrown for non-existing indices.
print(str1[2])   # output: x
  • The slice-operator [start:], [start:end], [:end]
    • Negative integer can be used to start from the last. [-start:], [-start:-end], [:-end]
print(str1[2:7])   # output: xt en
  • Iteration through characters.
for c in str1:
  print(c)

 

Update

  • You cannot modify a string since it is immutable.

Methods

  • str1.format().
msg = "Hello {}!".format("John")
print(msg)   # output: Hello John!
  • str1.split(delimeter_str).
print(str1.split(" "))
# output: ['Text', 'enclosed', 'with', 'single', 'quotes.']
  • str1.replace(search_str, replace_str).
    • It won’t modify the existing string but return the modified string.
new_str = str1.replace("enclosed with", "and")
print(new_str)   # output: Text and single quotes.

Operators

  • Concatenation operator: +
userName = "John"
msg = "Hello " + userName
print(msg)   # output: Hello John
  • Multiplication operator:  * 
msg = 3 * "AB"
print(msg)   # output: ABABAB

 

 

Interview Questions

 

1. When you access a character using subscript operator, Do you get an element of type character or string?

There is no character type in python. It is a string of length 1.