String manipulation in Python

This article explains string manipulation in Python.

You can learn about various string manipulations, such as creating and concatenating strings, searching, and replacing, along with code samples.

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String manipulation in Python

There are various ways to manipulate strings in Python. Below is an introduction to commonly used string operations.

Creating strings

In Python, strings can be created using single quotes ('), double quotes ("), or triple quotes (''', """).

1single_quoted = 'Hello'
2double_quoted = "World"
3multi_line = '''This is
4a multi-line
5string'''
6
7print(single_quoted)
8print(double_quoted)
9print(multi_line)

• This code demonstrates how to create and display strings in Python using single quotes, double quotes, and triple quotes.

String concatenation

To concatenate strings, use the + operator, f-strings, or the str.format method.

 1# + operator
 2name = "John"
 3greeting = "Hello, " + name + "!"
 4print(greeting)
 5
 6# f-string (available in Python 3.6 and above)
 7greeting_f = f"Hello, {name}!"
 8print(greeting_f)
 9
10# str.format method
11greeting_format = "Hello, {}!".format(name)
12print(greeting_format)

• This code shows how to concatenate strings in Python using the + operator, f-strings, and the str.format method.

Repeating strings

To repeat strings, use the * operator.

1repeat = "ha" * 3  # Result: "hahaha"
2print(repeat)

• This code demonstrates how to repeat strings in Python using the * operator.

Length of a string

To get the length of a string, use the len function.

1name = "John"
2greeting = "Hello, " + name + "!"
3
4# Returns the length of the string greeting
5length = len(greeting)
6print(length)

• This code shows how to get the length of a string in Python using the len function.

Indexing and slicing

Use indexing or slicing to retrieve specific characters or substrings within a string.

 1word = "Python"
 2
 3first_char = word[0]    # P
 4last_char = word[-1]    # n
 5print(first_char)
 6print(last_char)
 7
 8# Slice
 9sliced_word = word[1:4] # yth
10reversed_word = word[::-1] # nohtyP
11print(sliced_word)
12print(reversed_word)

• This code demonstrates how to retrieve specific characters or substrings from a string in Python using indexing and slicing.

Processing each character

Since strings are treated as sequence types, you can process each character using a for loop.

1text = "Python"
2
3# Iterate each character
4for char in text:
5    print(char)

• {^ i18n_speak このコードは、文字列 Python を1文字ずつ取り出して順番に表示する方法を示しています。^}

Searching and replacing in strings

Use the str.find and str.replace methods to search and replace in strings.

1sentence = "She sells sea shells on the sea shore."
2
3# Returns the index of the first occurrence of "sea": 10
4index = sentence.find("sea")
5print(index)
6
7# Replace "sea" with "ocean"
8replaced_sentence = sentence.replace("sea", "ocean")
9print(replaced_sentence)

• This code shows how to search for a string using the str.find method and replace a string using the str.replace method in Python.

Converting case in strings

To convert strings to uppercase or lowercase, use str.upper, str.lower, str.capitalize, or str.title.

 1text = "hello world"
 2upper_text = text.upper()       # "HELLO WORLD"
 3lower_text = text.lower()       # "hello world"
 4capitalized_text = text.capitalize() # "Hello world"
 5title_text = text.title()       # "Hello World"
 6
 7print(upper_text)
 8print(lower_text)
 9print(capitalized_text)
10print(title_text)

• This code demonstrates how to convert strings to uppercase, lowercase, and title case in Python.

Splitting and joining strings

To split a string by a specific delimiter, use str.split, and to join elements of a list, use str.join.

1csv = "apples,bananas,cherries"
2fruits = csv.split(",")  # ["apples", "bananas", "cherries"]
3joined_fruits = ", ".join(fruits)  # "apples, bananas, cherries"
4
5print(fruits)
6print(joined_fruits)

• This code shows how to split a string using str.split and join list elements using str.join in Python.

Removing whitespace

To remove whitespace from a string, use str.strip, str.lstrip, or str.rstrip.

1whitespace = "   hello   "
2stripped = whitespace.strip()   # "hello"
3lstripped = whitespace.lstrip() # "hello   "
4rstripped = whitespace.rstrip() # "   hello"
5
6print(stripped)
7print(lstripped)
8print(rstripped)

• This code demonstrates how to remove leading and trailing whitespace or whitespace from either side of a string in Python using str.strip, str.lstrip, and str.rstrip.

Summary

By combining these operations, various string manipulations can be performed in Python.

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