Strip a list item for extracting a specific value in python

Question

I have a list, which was produced as output of a python script in the following format:

[' (* 100.856 UnitA', ') [ 98.0%]',
 ' (* 100.598 UnitB', ') [ 98.0%]', 
 ' (*  98.193 UnitC', ') [ 25.6%]']

Now, I am interested to put the floating point values in every list item to a new list for further processing in a python script. Is there a way (an in-built python function maybe) I can strip the floating point content alone to a new list? In the above example my desired output would be like :

[100.856,98.0,100.598,98.0,98.193,25.6]

If not an in-built function, any other alternate way I can achieve this?

This could be done simply in a loop or a list comprehension. What have you tried so far? — SiHa, Mar 23 '16 at 10:56
I tried using extend. Realized won't work. New to python. So, wanted to explore the options. — skrowten_hermit, Mar 23 '16 at 11:18

score 4 · Accepted Answer · edited May 23 '17 at 12:31

Using a regex pattern from here will extract the floats and cast to float as desired:

In [153]:
l=[' (* 100.856 UnitA', ') [ 98.0%]',
 ' (* 100.598 UnitB', ') [ 98.0%]', 
 ' (*  98.193 UnitC', ') [ 25.6%]']
import re
[float(re.findall(r'(-?\d+\.\d+)',x)[0]) for x in l]

Out[153]:
[100.856, 98.0, 100.598, 98.0, 98.193, 25.6]

So the tricky thing here is that you need to search for digits \d but also search for the decimal point and trailing digits

Strip a list item for extracting a specific value in python

1 Answers1