如果分配了变量，则检查python中的某些条件

Question

I am coding in python. My problem is I have a variable strGUID in the function and then there is an if control flow in which I want to check if the variable is assigned and if yes then check on some condition on it. Clarifying piece of code is follows :

for line in data_list:
    if line.find('Project')!=-1
      strGUID = line.split(',')[2].strip('" ')
    if flag == False and line.find(strGUID)==-1 :
      print 'wrote line : ', line

In the above code I get an error sometimes saying

that the variable strGUID is accesses before its assignment.

so what I want to do is to check in the second if loop if the variable strGUID is defined and if it is then check for condition : line.find(strGUID)==-1 . Something like

if flag == False and (if strGUID then line.find(strGUID)==-1) :

PS : this is just to shorten the code and make it intelligent, I know that I can write longer lengthier if checks in the code, so asking for that is not the purpose.

clarification : In case if you want to suggest the answer where you initialli assign strGUID = None and then check it in the second if loop, I want to execute print even when the strGUID is None. Hence I am searching for an intelligent way of defining if condition. ie I want print to get executed if strGUID = None or if strGUID is not None and line.find(strGUID)==-1

edit : basically my current code has second if loop as :

if flag == False and (strGUID is None or (strGUID is not None and line.find(strGUID)==-1) ) :

I want to check if there is an intelligent way to shorten it.

Answer 1

The customary way to do this would be to set strGUID = None at the start, and then check

if flag == False and (strGUID is not None and line.find(strGUID) == -1):

If the first part ( strGUID is not None ) is false, the second part ( line.find(strGUID) == -1 ) will never be evaluated.