def readf(filename):
lines = file(filename).readlines()
dic = {}
for i in lines:
i_ = i.split()
dic[i_[0]] = int(i_[1])
return dic
dica = readf('a.txt')
dicb = readf('b.txt')
lines = []
for i in dica:
percent = str(float(dicb[i])*100/dica[i])+'%'
s = ' '.join([i, str(dica[i]), str(dicb[i]), percent])
s += '\n'
lines.append(s)
with open('c.txt', 'w') as f:
f.writelines(lines)
f.close()