字符串操作

>>> print("spam" * 3)
spamspamspam

>>> 4 * '2'
'2222'

>>> '17' * '87'
TypeError: can't multiply sequence by non-int of type 'str'
# 类型错误：字符串不能和非整数类型相乘

>>> 'pythonisfun' * 7.0
TypeError: can't multiply sequence by non-int of type 'float'
# 类型错误：浮点数不能和非整数类型相乘