Why does lambda throw 'name value_o is not defined' error?

[karabakh]

Note that this is happening in codewars and my IDE is not showing any errors.

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def decrypt(text,n):     i=0     test=""     if n<0:         text=text     else:         while i<n:             for index,value in enumerate(text):                 global value_e                 value_e=[value for index, value in enumerate(text) if index<len(text)/2]                 global value_o                 value_o=[value for index, value in enumerate(text) if index>=len(text)/2]             i+=1     print(value_o)     for x in map(lambda x,y : x+y, value_o, value_e):         test+= x

here's the error:
Traceback (most recent call last):
File "main.py", line 12, in <module>
Test.assert_equals(decrypt("This is a test!", 0), "This is a test!")
File "/home/codewarrior/solution.py", line 14, in decrypt
for x in map(lambda x,y : x+y, value_o, value_e):
NameError: name 'value_o' is not defined


Thank you

[Axel_Erfurt]

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def decrypt(text,n):     value_e = []     value_o = []     i=0     test=""     if n<0:         text=text     else:         while i<n:             for index,value in enumerate(text):                 value_e=[value for index, value in enumerate(text) if index<len(text)/2]                 value_o=[value for index, value in enumerate(text) if index>=len(text)/2]             i+=1     print(value_e)     print(value_o)     for x in map(lambda x,y : x+y, value_o, value_e):         test+= x

decrypt("hello world", 11)

Output:
['h', 'e', 'l', 'l', 'o', ' ']
['w', 'o', 'r', 'l', 'd']

[deanhystad]

if n == 0 this code never runs:

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for index,value in enumerate(text):     global value_e     value_e=[value for index, value in enumerate(text) if index<len(text)/2]     global value_o     value_o=[value for index, value in enumerate(text) if index>=len(text)/2]

If that code doesn't run, value_e and value_o are not defined. You would get the same error running this code in you IDE if the first time you called decrypt you passed n == 0. However if you call decrypt() with n != 0 it will define value_e and value_o in the global scope and a future decrypt() call with n == 0 will will give invalid results but not crash.

[karabakh]

if n == 0 this code never runs:

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for index,value in enumerate(text):     global value_e     value_e=[value for index, value in enumerate(text) if index<len(text)/2]     global value_o     value_o=[value for index, value in enumerate(text) if index>=len(text)/2]

If that code doesn't run, value_e and value_o are not defined. You would get the same error running this code in you IDE if the first time you called decrypt you passed n == 0. However if you call decrypt() with n != 0 it will define value_e and value_o in the global scope and a future decrypt() call with n == 0 will will give invalid results but not crash.

Now I see where it went wrong. Thanks a lot!