define variables in the txt file using python

[Xristos Xristoou]

Τη Σάββατο, 8 Οκτωβρίου 2016 - 12:25:28 π.μ. UTC+3, ο χρήστης Xristos Xristoou έγραψε:
> hello
> 
> 
> i have one .txt file and i want to create python script with sys.argv or argparse or other package to define some variables in the txt file and i take some result.
> 
> 
> 
> txt file maybe like this :
> 
> input number 1= %var1%
> input number 2= %var2%
> result = %vresult(var1-var2)%
> 
> how can i write a python script to update dynamic variables in the txt file ?
> i dont want with replace i thing so arguments is the better.

thanks Mr.Peter your code look nice,i have one question,must be running from cmd line ?i cant to run your code in the python script ?