Question

I want to extract and print a variable number ‘-34.99’ from the string:

myString = "Test1 [cm]:     -35.00/-34.99/-34.00/0.09"

The values in the string will change.
How can I do it with the regular expression in Python?

Thanks in advance

Answer 1

Non-regex solution is:

myString = "Test1 [cm]:     -35.00/-34.99/-34.00/0.09"  
print myString.split("/")[1]

Test this code here.

---

One of regex solutions would be:

import re 
myString = "Test1 [cm]:     -35.00/-34.99/-34.00/0.09" 
print re.search(r'(?<=\/)[+-]?\d+(?:\.\d+)?', myString).group()

Test this code here.

Explanation:

(?<=\/)[+-]?\d+(?:\.\d+)?
└──┬──┘└─┬─┘└┬┘└───┬────┘
   │     │   │     │
   │     │   │     └ optional period with one or more trailing digits
   │     │   │
   │     │   └ one or more digits
   │     │
   │     └ optional + or -
   │
   └ leading slash before match