How to Alter a Word in a String Python

In Python, strings are immutable, which means that once a string is created, it cannot be altered directly. However, you can create a new string by concatenating or using other string manipulation techniques. This article will guide you through the various methods to alter a word in a string in Python.

1. Using String Concatenation

One of the simplest ways to alter a word in a string is by using string concatenation. You can replace the word you want to change with a new one by concatenating it with the rest of the string.

“`python
original_string = “Hello world”
word_to_replace = “world”
new_word = “Python”

new_string = original_string.replace(word_to_replace, new_word)
print(new_string)
“`

Output:
“`
Hello Python
“`

In the above example, we used the `replace()` method to replace the word “world” with “Python” in the `original_string`.

2. Using String Splitting and Joining

Another method to alter a word in a string is by splitting the string into a list of words, modifying the specific word, and then joining the list back into a string.

“`python
original_string = “Hello world”
word_to_replace = “world”
new_word = “Python”

words = original_string.split()
words[1] = new_word
new_string = ” “.join(words)
print(new_string)
“`

Output:
“`
Hello Python
“`

In this example, we split the `original_string` into a list of words using the `split()` method. Then, we modified the second word (index 1) to “Python” and joined the list back into a string using the `join()` method.

3. Using String Formatting

String formatting is another way to alter a word in a string. You can use placeholders to replace specific parts of the string with new values.

“`python
original_string = “Hello {word}”
word_to_replace = “world”
new_word = “Python”

formatted_string = original_string.format(word=new_word)
print(formatted_string)
“`

Output:
“`
Hello Python
“`

In this example, we used curly braces `{}` as placeholders for the word we want to replace. By using the `format()` method, we replaced the placeholder `{word}` with the new word “Python”.

4. Using Regular Expressions

Regular expressions (regex) are a powerful tool for string manipulation. You can use them to find and replace specific patterns in a string.

“`python
import re

original_string = “Hello world”
word_to_replace = “world”
new_word = “Python”

pattern = re.compile(r’\b’ + word_to_replace + r’\b’)
new_string = pattern.sub(new_word, original_string)
print(new_string)
“`

Output:
“`
Hello Python
“`

In this example, we used the `re.compile()` function to compile a regex pattern for the word we want to replace. Then, we used the `sub()` method to replace the matched word with the new word “Python”.

In conclusion, there are several methods to alter a word in a string in Python. Depending on your requirements, you can choose the method that suits you best. Whether it’s using string concatenation, splitting and joining, string formatting, or regular expressions, these techniques will help you achieve your desired result.