NameError with exec function

Question

I'm a newbie in Python. I'm trying to apply some dynamics function ( startswith() , replace() , exec..) defined as string.

I've this code:

access_number = 'CF-12345' 
condition = 'str({v}).startswith("CF-", 0)'

result = {}
exec (condition.format(v = access_number)) in r

but I've this error:

Traceback (most recent call last):                                                                                                                   
  File "/home/main.py", line 11, in <module>                                                                                                         
    exec (condition.format(v = access_number)) in r                                                                                                  
  File "<string>", line 1, in <module>                                                                                                               
NameError: name 'CF' is not defined  

I don't know what I'm doing wrong.

Any help would be appreciated.

Answer 1

Try using print statements as your diagnostic, if you run

access_number = 'CF-12345'
condition = 'str({v}).startswith("CF-", 0)'

result = {}
print condition
print condition.format(v=access_number)
exec (condition.format(v = access_number)) in result

the output is

str({v}).startswith("CF-", 0)
str(CF-12345).startswith("CF-", 0)
Traceback (most recent call last):
File "stuff.py", line 8, in <module>
exec (condition.format(v = access_number)) in result
File "<string>", line 1, in <module>
NameError: name 'CF' is not defined

Notice the second line has str(CF-1234) this is trying to subtract 1234 from the variable CF.

try

access_number = '"CF-12345"'
condition = 'str({v}).startswith("CF-", 0)'

result = {}
exec (condition.format(v = access_number)) in result