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Learn how to effectively use `regex` in Python to extract left and right text surrounding a specific word in a string, such as "for".
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How to Use Regex to Obtain Left and Right Text from a String in Python

When working with strings in Python, you might find yourself needing to extract specific pieces of information based on certain keywords. Imagine you have the string '4 for 9' and you want to obtain the numbers on both sides of the word for.

Using built-in methods like split can work, but employing regular expressions (regex) allows for more flexibility and precision in how you extract the data. In this guide, we'll explore how to use regex to achieve this in Python.

The Problem

Given a string:

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Our goal is to extract:

The text to the left of for (in this case, 4)

The text to the right of for (in this case, 9)

Why Use Regex?

Regular expressions are powerful tools for string manipulation. They enable you to match patterns and can be especially useful when dealing with complex strings where the structure may vary.

The Solution

Step 1: Import the Regex Module

First, import the re module, which provides support for working with regular expressions in Python.

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Step 2: Define the Regex Pattern

We can define a regex pattern that captures the left and right texts. Here’s the regex pattern:

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This pattern does the following:

([\s\S]*): This captures any character (including spaces) before for.

for: This matches the specific word we are interested in.

([\s\S]*): This captures any character (including spaces) after for.

Step 3: Use the Pattern to Match the String

Now, let's apply this regex pattern to our string:

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Step 4: Extract the Results

The groups() method returns a tuple containing the matched groups. For our case, running the above code will give:

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This result indicates that we have successfully captured the left and right text surrounding the word for.

Working with Different Strings

The regex solution is not limited to just one string. You can apply it to other variations as well:

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In each case, the regex neatly extracts the text before and after for.

Customizing the Regex

Matching Only Numbers: If you want to refine your regex to capture only numbers on both sides of for, modify your regex to:

[[See Video to Reveal this Text or Code Snippet]]

This pattern ensures that only digits are matched, making your results more tailored.

Conclusion

Using regex to extract text surrounding keywords in strings can greatly simplify your coding tasks. By following the steps outlined above, you can retrieve the left and right texts efficiently. Regular expressions are indeed a powerful feature of Python that can help streamline various text-processing tasks.

Feel free to apply this method to your own string parsing needs and enhance your Python programming skills!