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Regular expressions are a very powerful method for matching patterns in text.

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Regular expressions are used for a variety of purposes, from simple search and

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replace operations to complex text and data file manipulation.

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Regular expressions are actually a small language in itself.

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Regular expressions can be very simple or they can be very complex.

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Entire books have been written on the subject of regular expressions.

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If you are moderately familiar with how they work and what they look like,

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you can get a lot of power out of them using Python's regular expression module.

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Regular expressions are implemented in Python with the re module.

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This is Python's regular expression module and it's distributed with Python.

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So if you have Python, you have the re module.

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How it works looks like this.

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You import re and you compile a pattern and then you use the pattern to search

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and replace or to perform whatever manipulations you are going to perform using

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the regular expressions.

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So let's go ahead and look at how we use regular expressions in Python.