How to parse for tags with '+' in python

Question

I'm getting a "nothing to repeat" error when I try to compile this: ``` search = re.compile(r'([^a-zA-Z0-9])(%s)([^a-zA-Z0-9])' % '+test', re.I) ``` The problem is the '+' sign. How should I handle that?

Accepted Answer

```
re.compile(r'([^a-zA-Z0-9])(%s)([^a-zA-Z0-9])' % '\+test', re.I)
```

The "+" is the "repeat at least once" quantifier in regular expressions. It must follow something that is repeatable, or it must be escaped if you want to match a literal "+".

Better is this, if you want to build your regex dynamically.

```
re.compile(r'([^a-zA-Z0-9])(%s)([^a-zA-Z0-9])' % re.escape('+test'), re.I)
```

How to parse for tags with '+' in python

Solution

Problem