您不能更改“”.format(),因为它是内置的,但如果可以为方法提供字符串和参数：

print(kf.format("{:t{}} {}", key, ':', value))

您可以通过继承string.Formatter来允许空格式字段并提供特殊类型处理程序来实现：

from string import Formatter

import sys

if sys.version_info < (3,):

int_type = (int, long)

else:

int_type = (int)

class TrailingFormatter(Formatter):

def vformat(self, *args):

self._automatic = None

return super(TrailingFormatter, self).vformat(*args)

def get_value(self, key, args, kwargs):

if key == '':

if self._automatic is None:

self._automatic = 0

elif self._automatic == -1:

raise ValueError("cannot switch from manual field specification "

"to automatic field numbering")

key = self._automatic

self._automatic += 1

elif isinstance(key, int_type):

if self._automatic is None:

self._automatic = -1

elif self._automatic != -1:

raise ValueError("cannot switch from automatic field numbering "

"to manual field specification")

return super(TrailingFormatter, self).get_value(key, args, kwargs)

def format_field(self, value, spec):

if len(spec) > 1 and spec[0] == 't':

value = str(value) + spec[1] # append the extra character

spec = spec[2:]

return super(TrailingFormatter, self).format_field(value, spec)

kf = TrailingFormatter()

w = 20

ch = ':'

x = dict(a_key=23, another_key=42)

for k in sorted(x):

v = x[k]

print(kf.format('{:t{}

给你：

a_key: 23

another_key: 42

您当然可以对ch和w值进行硬编码：

print(kf.format('{:t:<20} {}', k, v))

为了更好的可读性,但灵活性较差.

Python 3.4 string.Formatter()的backport包含版本(至少)高达3.5.0rc1的错误修复,包含此代码现在可在PyPI上获得