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Python Language – Strings and String Manipulation

Strings and String Manipulation in Python

Strings are fundamental data types in Python, representing text and characters. They play a vital role in many applications, from data processing to web development. This guide explores strings, their properties, and the various ways to manipulate and work with them.

Creating and Initializing Strings

You can create strings in Python by enclosing text in either single (‘ ‘) or double (” “) quotes:


single_quoted_string = 'Hello, Python!'
double_quoted_string = "Hello, Python!"

Both single and double quotes work, and you can choose the style that suits your preference. Strings can also span multiple lines by using triple quotes (”’ ‘ ”’):


multi_line_string = '''
This is a multi-line string.
It can span several lines.
'''
String Concatenation

String concatenation is the process of combining two or more strings to create a new one. In Python, you can concatenate strings using the ‘+’ operator:


first_name = "John"
last_name = "Doe"

full_name = first_name + " " + last_name

Python also supports string repetition using the ‘*’ operator:


greeting = "Hello, "
repeated_greeting = greeting * 3
String Indexing and Slicing

Strings are indexed, which means you can access individual characters by their position. Python uses a zero-based index:


text = "Python"

first_character = text[0]  # 'P'
second_character = text[1]  # 'y'

Python also allows you to slice strings, which means extracting a portion of the string. You specify a start and end index to define the slice:


text = "Python Programming"

# Slicing from index 0 to 5 (exclusive)
substring = text[0:5]  # 'Pytho'
String Methods

Python provides a variety of built-in methods for string manipulation:

  • len(): Returns the length of the string.
  • upper() and lower(): Convert the string to uppercase or lowercase, respectively.
  • strip(): Removes leading and trailing whitespace from the string.
  • split(): Splits the string into a list of substrings based on a specified separator.
  • replace(): Replaces a specified substring with another string.
  • find() and index(): Search for a substring and return its index. The difference is that find() returns -1 if not found, while index() raises an exception.