Using a text file to receive a string for a variable in Python, without defining it -

i have text file in there several variables. of them used in bash script of mine, i'd use same text file python script. lines not formatted python, want script ignore. formatted, want script check , if it's variable i'm looking - use it.

import sys import re

for ln in open("thefile.txt"):         m = re.match(r"(?p<varname>[^=]*)\s*=\s*(?p<value>.+)", ln)         if m:                 varname = m.group("varname")                 value_string = m.group("value")                 value = eval(value_string)                 print value                 # if variables name thisvariable, value:                 if varname == "thisvariable":                         mypythonvariable == value 

i'm getting following error:

nameerror: name 'somevariableinmytextfile' not defined

the somevariableinmytextfile first variable in file.

my question:

do have define every variable in txt file, in order rid of error? if not, shall do? i'm new @ python. first program.

the error eval complaining contents of value_string have no meaning whatever-it-is.

the real error using eval @ all. (a post on pitfalls can found here.) you don't need eval here - leaving value_string string regex gave just fine.

the problem present approach

sample thefile.txt:

foo=bar baz=42 quux=import os; os.shutdown() 

• when parsing foo, python complains bar isn't defined. (simple.)
• when parsing bar, python gives int instead of str. (no real problem...)
• when parsing quux, python shuts down computer. (uh oh!)

why don't need eval

you want string value, correct? regex gives string!

varname = m.group("varname") value = m.group("value") print value if varname == "thisvariable":     mypythonvariable = value # meant = instead of ==?