python - 在格式字符串中使用参数

Question

这个:

print '{:x<4d}'.format(34)

打印这个:

34xx

我该怎么做:

width = 13
print '{:x<|width|d}'.format(34)

要得到这个:

34xxxxxxxxxxx

Answer 1

您可以将一个格式字段放在另一个格式字段中:

>>> width = 13
>>> print '{:x<{}d}'.format(34, width)
34xxxxxxxxxxx
>>>

来自docs :

A format_spec field can also include nested replacement fields within it. These nested replacement fields can contain only a field name; conversion flags and format specifications are not allowed. The replacement fields within the format_spec are substituted before the format_spec string is interpreted. This allows the formatting of a value to be dynamically specified.

但请注意，嵌套只能深入一层。