(xyz)的表示在python中是什么意思

这是 string formatting using keys :

>>> d = {"answer": 42}
>>> "the answer is %(answer)d" % d
'the answer is 42'

它通过从字典中选取值来格式化字符串:

test = { "foo": 48,  "bar": 4711, "hello": "yes" }
print "%(foo)d %(bar)d and %(hello)s" % test

印刷品:

48 4711 and yes