test with python global keyword

python_global_keyword.py

WORD_FEATURES = []
def overwrite_word_features():
 WORD_FEATURES = [1, 3, 5 ]

overwrite_word_features()
print WORD_FEATURES # prints []

#This took me a while to guess what could have been happening and was confirmed upon googling. the correct way to do is

WORD_FEATURES = []
def overwrite_word_features():
global WORD_FEATURES #tell python that in the following code WORD_FEATURES is global
 WORD_FEATURES = [1, 3, 5 ]

overwrite_word_features()
print WORD_FEATURES # prints [1, 3, 5 ]

#How about if we assign the variable first and then declare as global it gives syntax warning "SyntaxWarning: name 'WORD_FEATURES' is assigned to #before global declaration" but still the global variable is assigned.

WORD_FEATURES = []
def overwrite_word_features():
WORD_FEATURES = [10, 9, 8 ]
global WORD_FEATURES #tell python that in the following code WORD_FEATURES is global
 WORD_FEATURES += [1, 3, 5]

overwrite_word_features()
print WORD_FEATURES # prints [10, 9, 8, 1, 3, 5]