July 2019
Intermediate to advanced
365 pages
8h 13m
Chinese
Content preview from Python机器学习手册：从数据预处理到深度学习
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3.3
浏览数据帧
｜
37
数值型的值代表的是分类（例如，如果
Survived
等于
1
，就表示乘客在此次海难中幸存）。
由于这个原因，一些描述性统计量，比如
SexCode
（代表乘客的性别）列的标准差，不
能提供很直观的结论。
3.3
浏览数据帧
问题描述
从一个数据帧中挑出单个数据或一部分数据。
解决方案
使用
loc
或
iloc
能选择一个或多个数据，也能选择一行或多行数据 ：
#
加载库
import pandas as pd
#
创建
URL
url = 'https://tinyurl.com//titanic-csv'
#
加载数据
dataframe = pd.read_csv(url)
#
选择第一行
dataframe.iloc[0]
Name Allen, Miss Elisabeth Walton
PClass 1st
Age 29
Sex female
Survived 1
SexCode 1
Name: 0, dtype: object
可以使用冒号“
:
”来定义想要选择哪些行。比如选择第
2
、
3
、
4
行：
#
选择三行
dataframe.iloc[1:4]
我们甚至还能获取到某一行为止的所有行，比如获取到第
4
行为止的所有行 ：
#
获取到第
4
行为止的所有行
dataframe.iloc[:4]
38
｜
第
3
章
数据整理
Name PClass Age Sex Survived SexCode
1 Allison, Miss Helen Loraine 1st 2.0 female
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