尝试乘以元组元素时字符串格式错误 - python

Question

If

>>> (1,2)*2
>>> (1,2,1,2)

why isn't this working?

'%d %d %d %d' % (1,2)*2

TypeError: not enough arguments for format string

Is there another way to do this without having to explicitly construct the tuple?

Answer 1

You need to add a pair of parentheses:

'%d %d %d %d' % ((1,2)*2)

In Python, % and * have the same precedence , so your code is equivalent to

('%d %d %d %d' % (1,2))*2

The reason the two operators have the same precedence is that % is also the remainder operator, and thus is considered to be in the same category as multiplication and division.

Answer 2

Just add an extra pair of parenthesis:

>>> '%d %d %d %d' % ((1,2)*2)
'1 2 1 2'
>>>

As it currently stands, your code is trying to make the string using (1,2) and then multiply that string by 2.