从字符串中提取数字的pythonic方法

Question

I am developing a program to read through a CSV file and create a dictionary of information from it. Each line in the CSV is essentially a new dictionary entry with the delimited objects being the values.

As one subpart of task, I need to extract an unknown number of numeric digits from within a string. I have a working version, but it does not seem very pythonic.

An example string looks like this:

variable = Applicaiton.Module_Name.VAR_NAME_ST12.WORD_type[0]

variable is string's name in the python code, and represents the variable name within a MODBUS. I want to extract just the digits prior to the .WORD_type[0] which relate to the number of bytes the string is packed into.

Here is my working code, note this is nested within a for statement iterating through the lines in the CSV. var_length and var_type are some of the keys , ie {"var_length": var_length}

if re.search(".+_ST[0-9]{1,2}\\.WORD_type.+", variable):
    var_type = "string"
    temp = re.split("\\.", variable)
    temp = re.split("_", temp[2])
    temp = temp[-1]
    var_length = int(str.lstrip(temp, "ST")) / 2

Answer 1

You could maybe try using matching groups like so:

import re

variable = "Applicaiton.Module_Name.VAR_NAME_ST12.WORD_type[0]"
matches = re.match(r".+_ST(\d+)\.WORD_type.+", variable)
if matches:
    print(matches[1])

matches[0] has the full match and matches[1] contains the matched group.