在Python中只打印一定数量的字符

Question

Possible Duplicate:
Iterate an iterator by chunks (of n) in Python?

假设我在一个变量中存储了492个字符的字符串。如何打印前50个字符，然后转到下一行，然后打印下50个字符，最后打印一行42个字符？

Answer 1

chars_per_line = 50
for i in range(0, len(s), chars_per_line):
    print s[i:i+chars_per_line]

Answer 2

for line in mystring.splitlines():
    print line[:50]

Answer 3

In [363]: mystr = "A"*492

In [364]: print '\n'.join(mystr[i*width:(i+1)*width] for i in range(int(math.ceil(float(len(mystr))/width))))
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA