Вы можете сделать это примерно так:
with open('file1', 'rU') as f:
for line in f:
# split the line (only once) on a comma
value, rest = line.split(',', 1)
# join the line back together, but change the 1/0 to true/false
print(','.join(('true' if int(value) else 'false', rest)))
Результаты:
false,@rodriigoCabrera y tu vaso tu silla y tu baño
true,Mexican rival demands vote recount: The leader of Mexico's leftist Party of the Democratic Revolution, Andres Ma...
false,Queretaro 0 - 3 Morelia Tarjeta amarilla a Carlos Adrián Morales Higuera