Count the word frequencies of text file

FrequencyCount.py

import csv

data = open('data.txt', 'r')
for line in data.readlines():
	tokens = line.split()

# iterate througt the list
# count the existence
d = {}
for word in tokens:
	if word in d:
		d[word] = d[word] + 1
	else:
		d[word] = 1

with open('mycsvfile.csv', 'wb') as f:  # Just use 'w' mode in 3.x
    w = csv.DictWriter(f, d.keys())
    w.writerow(d)