习题 6: 字符串(string)和文本¶

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20``` ```x = "There are %d types of people." % 10 binary = "binary" do_not = "don't" y = "Those who know %s and those who %s." % (binary, do_not) print x print y print "I said: %r." % x print "I also said: '%s'." % y hilarious = False joke_evaluation = "Isn't that joke so funny?! %r" print joke_evaluation % hilarious w = "This is the left side of..." e = "a string with a right side." print w + e ```

你应该看到的结果¶

 ```1 2 3 4 5 6 7 8``` ```\$ python ex6.py There are 10 types of people. Those who know binary and those who don't. I said: 'There are 10 types of people.'. I also said: 'Those who know binary and those who don't.'. Isn't that joke so funny?! False This is the left side of...a string with a right side. \$ ```

加分习题¶

1. 通读程序，在每一行的上面写一行注解，给自己解释一下这一行的作用。
2. 找到所有的”字符串包含字符串”的位置，总共有四个位置。
3. 你确定只有四个位置吗？你怎么知道的？没准我在骗你呢。
4. 解释一下为什么 we+ 连起来就可以生成一个更长的字符串。

常见问题回答¶

%r%s 有什么不同？
%r 用来做 debug 比较好，因为它会显示变量的原始数据（raw data），而其它的符号则是用来向用户显示输出的。

%r 用来 debug 最好，而其它格式符则是用来向用户显示输出的。