Python Pandas Dataframe动态添加列
Python Pandas Dataframe动态添加列
提问于 2018-06-01 04:13:33
我的数据框如下：
Date Country GDP
0 2011 United States 345.0
1 2012 United States 0.0
2 2013 United States 457.0
3 2014 United States 577.0
4 2015 United States 0.0
5 2016 United States 657.0
6 2011 UK 35.0
7 2012 UK 64.0
8 2013 UK 54.0
9 2014 UK 67.0
10 2015 UK 687.0
11 2016 UK 0.0
12 2011 China 34.0
13 2012 China 54.0
14 2013 China 678.0
15 2014 China 355.0
16 2015 China 5678.0
17 2016 China 345.0我想计算一个国家每年在所有三个国家中的GDP百分比是多少。我想在dataframe中再添加一个名为parc的列：
我实现了以下代码：
import pandas as pd
countrylist=['United States','UK','China']
for country in countrylist:
for year in range (2011,2016):
df['perc']=(df['GDP'][(df['Country']==country) & (df['Date']==year)]).astype(float)/df['GDP'][df['Date']==year].sum()
print (df['perc'])我的输出如下
0 0.833333
1 NaN
2 NaN
3 NaN
4 NaN
5 NaN
6 NaN
7 NaN
8 NaN
9 NaN
10 NaN
11 NaN
12 NaN
13 NaN
14 NaN
15 NaN
16 NaN
17 NaN
0 NaN
1 0.0
2 NaN
3 NaN
4 NaN
5 NaN
6 NaN
7 NaN
8 NaN
9 NaN
10 NaN
11 NaN
12 NaN
13 NaN
14 NaN
15 NaN
16 NaN
17 NaN
0 NaN
1 NaN
2 0.384357
3 NaN
4 NaN
5 NaN
6 NaN
7 NaN
8 NaN
9 NaN
10 NaN
11 NaN
12 NaN
13 NaN
14 NaN
15 NaN
16 NaN
17 NaN……
我注意到，当新的循环开始时，我之前的结果被抹去了。所以最终我只有最后一个perc的值。当df‘’perc‘发生时，我应该提供一些位置信息，例如：
df['perc'][([(df['Country']==country) & (df['Date']==year)])]=(df['GDP'][(df['Country']==country) & (df['Date']==year)]).astype(float)/df['GDP'][df['Date']==year].sum()但它不起作用。如何动态插入值？
理想情况下，我应该：
Date Country GDP perc
0 2011 United States 345.0 0.81
1 2012 United States 0.0 0.0
2 2013 United States 457.0 0.23
3 2014 United States 577.0 xx
4 2015 United States 0.0 xx
5 2016 United States 657.0 xx
6 2011 UK 35.0 xx
7 2012 UK 64.0 xx
8 2013 UK 54.0 xx
9 2014 UK 67.0 xx
10 2015 UK 687.0 xx
11 2016 UK 0.0 xx
12 2011 China 34.0 xx
13 2012 China 54.0 xx
14 2013 China 678.0 xx
15 2014 China 355.0 xx
16 2015 China 5678.0 xx
17 2016 China 345.0 xx回答 1
Stack Overflow用户
发布于 2018-06-01 04:18:46
您可以在此处使用transform sum
df.GDP/df.groupby('Date').GDP.transform('sum')
Out[161]:
0 0.833333
1 0.000000
2 0.384357
3 0.577578
4 0.000000
5 0.655689
6 0.084541
7 0.542373
8 0.045416
9 0.067067
10 0.107934
11 0.000000
12 0.082126
13 0.457627
14 0.570227
15 0.355355
16 0.892066
17 0.344311
Name: GDP, dtype: float64页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/50632087
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