How to Grab Content Between Elements in Python using Regular Expressions

In this article, we show how to grab content between elements in Python using regular expressions.

So let's say we have a Python variable that contains HTML elements, such as <li></li> tags.

How can we grab information between HTML elements?

We can do this through the re.compile() function in Python.

So let's see how this looks below in code.

>>> import re >>> string1= "<ul><li>Item 1</li> <li>Item 2</li><li>Item 3</li><ul>" >>> regex= re.compile("<li>.*?</li>") >>> matches= re.findall(regex, string1) >>> print(matches) ['<li>Item 1</li>', '<li>Item 2</li>', '<li>Item 3</li>']

So this code gives us the <li></li> tags and the information in between them.

It uses lazy matching to give us each individual opening and closing li tag, with the content inside of them.

Another way to write the same regex is by the following, regex= re.compile("(<li>.*? </li>)")

But what if we only want to retrieve the content in between the li tags, but don't want to display the li tags themselves? How do we do this?

Well the re.compile() function allows for subexpressions using parentheses (). This is profound.

Anything that you place within parentheses is singled out to be the part that gets returned as the output.

So if we have the following regex variable, regex= re.compile("<li>(.*?) </li>"), the only part that gets returned is the content in between <li> and </li>.

This is shown in the code below.

>>> import re >>> string1= "<ul><li>Item 1</li> <li>Item 2</li> <li>Item 3</li><ul>" >>> regex= re.compile("<li>(.*?)</li>") >>> matches= re.findall(regex, string1) >>> print(matches) ['Item 1', 'Item 2', 'Item 3']

So now with parentheses in between the opening and closing li tags, only this area is returned as the output.

Again, parentheses represent a subexpression with the re.compile() function in Python.

If you want to return a subexpression in between 2 components in a text, then use parentheses to get the content in between.

If there are 2 opening and closing parentheses with the re.compile, 2 values are returned.

Let's say we have the following code shown below.

>>> import re >>> string1= "<ul><li>Item 1</li> <li>Item 2</li> <li>Item 3</li><ul>" >>> regex= re.compile("(<li>(.*?)</li>)") >>> matches= re.findall(regex, string1) >>> print(matches) [('<li>Item 1</li>', 'Item 1'), ('<li>Item 2</li>', 'Item 2'), ('<li>Item 3</li>', 'Item 3')]

You see in the regex variable that there are 2 opening and closing parentheses.

Thus, the re.compile() function will return 2 values.

Since one opening and closing parentheses encloses the entire HTML opening and closing li tag, it returns the entire expression composed of the opening and closing li tags. The other parentheses returns only the content in between the opening and closing li tags.

And this is how content can be grabbed between elements in Python using regular expressions.

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