1.

String Manipulation in Python

Answer»
  • Escape Sequences:

Escape Sequences are used to print certain characters to the output stream which carry special meaning to the language compiler.

Examples:

Escape SequenceResults in
\tTab Space
\nNewline
\\Backslash
\’Single Quote
  • Multiline Strings:

Multiline Strings are used in python through triple quotes '''

Example:

a = ''' Hello
World!
This is a
Multiline String.'''

print(a)
Output:
Hello
World!
This is a
Multiline String.
  • Strings Indexing:

Strings in Python are indexed the same way as a list of characters, based on 0-based indexing. We can access elements of a string at some index by using the [] operators.

Consider an example of the string value Python.

a = "Python"
print(a[0], a[2], a[4])
print(a[-1], a[-3], a[-5])
Output:
P t o
n h y
  • Strings Slicing:

Slicing is also done the same way as in lists.

a = "Hello"
# Slices the string from 0 to 3 indexes
print(a[0:3])
# Slices the string from 3 to -1(same as 4) indexes
print(a[3:-1])
Output:
Hel
l
  • Case Conversion Functions:

The upper() and lower() functions are used to convert a string of letters into uppercase or lowercase respectively.

The isupper() and islower() functions are used to check if a string is in all uppercase or lowercase respectively.

a = "Hello"
print(a)
# Converts string to uppercase
print(a.upper())
# Converts string to lowercase
print(a.lower())
# Checks if string is uppercase
print(a.isupper())
# Checks if string is lowercase
print(a.islower())
Output:
Hello
HELLO
hello
False
False

Other similar functions:

FunctionExplanation
isspace()Returns True if all characters in string are whitespaces
isalnum()Returns True if given string is alphanumeric
isalpha()Returns True if given character is alphabet
isTitle()Returns True if string starts with an uppercase letter and then rest of the characters are lowercase
  • join() and split() Functions:

join() function merges elements of a list with some delimiter string, and returns the result as a string.

list = ["One", "Two", "Three"]
# join function
s = ','.join(list)
print(s)
Output:
One,Two,Three

split() function splits the into tokens, based on some delimiters and returns the result as a list.

# split function
newList = s.split(',')
print(newList)
Output:
['One', 'Two', 'Three']

In general, a string can be split to list using split() method and a list can be joined to string using the join() method as shown in the image below:

  • String Formatting:

String Formatting is done with the str.format() function.

first = "first"
second = "second"
s = "Sunday is the {} day of the week, whereas Monday is the {} day of the week".format(first, second)
print(s)
Output:
Sunday is the first day of the week, whereas Monday is the second day of the week
  • Template Strings:

It is recommended to be used when formatting strings generated by users. They make the code less complex so are easier to understand. They can be used by importing the Template class from the string module.

Example:

>>> from string import Template
>>> name = 'Scaler'
>>> t = Template('Hey $name!')
>>> t.substitute(name = name)
'Hey Scaler!'


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