问题描述
我正在尝试使用 str.format()
方法,当我的值存储在元组中时遇到了一些困难.例如,如果我这样做:
s = "x{}y{}z{}"s.format(1,2,3)
然后我得到 'x1y2z3'
- 没问题.
但是,当我尝试:
s = "x{}y{}z{}"tup = (1,2,3)s.format(tup)
我明白
IndexError: 元组索引超出范围.
那么如何将元组转换"为单独的变量?或任何其他解决方法的想法?
使用 *arg
可变参数调用语法:
s = "x{}y{}z{}"tup = (1,2,3)s.format(*tup)
tup
之前的 *
告诉 Python 将元组解包为单独的参数,就好像您调用了 s.format(tup[0], tup[1], tup[2])
代替.
或者你可以索引第一个位置参数:
s = "x{0[0]}y{0[1]}z{0[2]}"tup = (1,2,3)s.format(tup)
演示:
>>>tup = (1,2,3)>>>s = "x{}y{}z{}">>>s.format(*tup)'x1y2z3'>>>s = "x{0[0]}y{0[1]}z{0[2]}">>>s.format(tup)'x1y2z3'I'm trying to use the str.format()
method, and having some difficulties when my values are stored within a tuple. For example, if I do:
s = "x{}y{}z{}"
s.format(1,2,3)
Then I get 'x1y2z3'
- no problem.
However, when I try:
s = "x{}y{}z{}"
tup = (1,2,3)
s.format(tup)
I get
IndexError: tuple index out of range.
So how can I 'convert' the tuple into separate variables? or any other workaround ideas?
Pass in the tuple using *arg
variable arguments call syntax:
s = "x{}y{}z{}"
tup = (1,2,3)
s.format(*tup)
The *
before tup
tells Python to unpack the tuple into separate arguments, as if you called s.format(tup[0], tup[1], tup[2])
instead.
Or you can index the first positional argument:
s = "x{0[0]}y{0[1]}z{0[2]}"
tup = (1,2,3)
s.format(tup)
Demo:
>>> tup = (1,2,3)
>>> s = "x{}y{}z{}"
>>> s.format(*tup)
'x1y2z3'
>>> s = "x{0[0]}y{0[1]}z{0[2]}"
>>> s.format(tup)
'x1y2z3'
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