字符串格式：％与.format

问题：

Python 2.6 introduced the str.format() method with a slightly different syntax from the existing % operator. Python 2.6引入了str.format()方法，其语法与现有的%运算符略有不同。 Which is better and for what situations? 哪个更好，什么情况下适合？

1. The following uses each method and has the same outcome, so what is the difference? 以下使用每种方法并具有相同的结果，那么有什么区别？

   #!/usr/bin/python sub1 = "python string!" sub2 = "an arg" a = "i am a %s" % sub1 b = "i am a {0}".format(sub1) c = "with %(kwarg)s!" % {'kwarg':sub2} d = "with {kwarg}!".format(kwarg=sub2) print a # "i am a python string!" print b # "i am a python string!" print c # "with an arg!" print d # "with an arg!"

2. Furthermore when does string formatting occur in Python? 此外，何时在Python中进行字符串格式化？ For example, if my logging level is set to HIGH will I still take a hit for performing the following % operation? 例如，如果我的日志记录级别设置为“高”，执行以下%操作是否还会受到影响？ And if so, is there a way to avoid this? 如果是这样，有办法避免这种情况吗？

   log.debug("some debug info: %s" % some_info)

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解决方案：

参考一： https://stackoom.com/question/LKB2/字符串格式-与-format
参考二： https://oldbug.net/q/LKB2/String-formatting-vs-format

来源：oschina

链接：https://my.oschina.net/u/3797416/blog/3220635