March 2022
Intermediate to advanced
522 pages
13h 52m
Chinese
Content preview from Python语言及其应用（第2版）
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数字
｜
41
如果你混用整数和浮点数，则
Python
会自动将整数提升为浮点数：
>>> 43 + 2.
45.0
Python
也会将布尔值提升为整数或浮点数。
>>> False + 0
0
>>> False + 0.
0.0
>>> True + 0
1
>>> True + 0.
1.0
3.4
数学函数
Python
支持复数并包含常用的数学函数，比如平方根、余弦函数等。第
22
章会继续讨论
在科学环境中运用
Python
。
3.5
后续内容
在第
4
章中，我们终于可以告别那些只有区区一行代码的
Python
示例了。有了
if
语句，
你会学到如何使用代码进行决策。
3.6
练习
本章介绍了
Python
的原子：数字、布尔值和变量。下面在交互式解释器中做几个小练习。
1.
一小时有多少秒
？使用交互式解释器作为计算器，用一分钟内的秒数（
60
）乘以一小时
内的分钟数（也是
60
）。
2.
将上一个练习的结果（一小时的秒数）赋给变量
seconds_per_hour
。
3.
一天有多少秒？利用
seconds_per_hours
变量进行计算。
4.
再次计算一天有多少秒，不过这次把结果保存在变量
seconds_per_day
中。
5.
使用浮点除法（
/
）将
seconds_per_day
除以
seconds_per_hour
。
6.
使用整数除法
（
//
）将
seconds_per_day
除以
seconds_per_hour
。除了最后的
.0
，结果
是否和上一个练习的浮点数值一样？
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.