July 2017
Intermediate to advanced
398 pages
11h 54m
Chinese
Content preview from Python数据处理
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数据清洗：研究、匹配与格式化
｜
135
print
duration
➋
print
duration.days
➌
print
duration.total_seconds()
➍
minutes = duration.total_seconds() / 60.0
➎
print
minutes
➊
用结束时间减去开始时间，计算出采访时长。
➋
打印一个新的
Python
日期类型。这是一个
timedelta
对象。
timedelta
会给出两个时间
对象的时间差，还可用于改变时间对象，详见
datetime
文档（
https://docs.python.org/2/
library/datetime.html?highlight=timedelta#datetime.timedelta
）。
➌
利用内置的
days
属性来查看
timedelta
对象里包含了多少天。
➍
调用
timedelta
对象的
total_seconds
方法，计算时间差包含多少秒。结果精确到微秒。
➎
计算分钟数，因为
timedelta
对象没有分钟属性。
运行代码，我们知道第一次采访时长
8
分钟——但这是不是采访的平均时长呢？利用刚学
的
datetime
模块中的方法解析整个数据集，我们可以计算出采访平均时长。我们前面做了
一些简单的
datetime
数学运算，并学习了如何利用数据集创建
Python
的
datetime
对象。
下面我们来看一下，能否将这些新的
datetime
对象重新转换成格式化字符串，用在报告中
可以提高可读性：
print
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