Deconstruct the oneliner

gistfile1.py

oneliner = 'output.writerow(map(lambda x: x[1], filter(lambda x: True if x[0] else False, zip(filter_map,line))))'

# First, we zip two lists together, in this case we take something like:
# x = [ {}, {}, {'one':1} ]
# y = [ [one, one, one], [two, two, two], [three, three, three] ]
# and turn it into:
# z = [ ({}, [one, one, one]), ({}, [two, two, two]), ({'one':1}, [three, three, three]) ]

test_list = zip(filter_map, line)

# then we want to exclude the items in that list where the first item is falsy.
# filter( lambda x: True if x[0] else False, test_list)
# but we can do that another way.

new_test_list = []
# di = the dictionary, line_data = a line of data from the file we are reading
for di, data_line in test_list:
    if di:
        # We only keep the data_line around because that's all we care about now
        new_test_list.append(data_line)

output.writerow(new_test_list)

#boom, row [ [three, three, three] ] is written to file.