获取总计 pandas 列

本文介绍了获取总计 pandas 列的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

目标

Target

我有一个Pandas数据框，如下所示，它具有多列，并希望获取列的总和，MyColumn.

I have a Pandas data frame, as shown below, with multiple columns and would like to get the total of column, MyColumn.

数据框 -df:

print df

X MyColumn Y Z 0 A 84 13.0 69.0 1 B 76 77.0 127.0 2 C 28 69.0 16.0 3 D 28 28.0 31.0 4 E 19 20.0 85.0 5 F 84 193.0 70.0

我的尝试 :

My attempt:

我尝试使用groupby和.sum()来获取列的总和:

I have attempted to get the sum of the column using groupby and .sum():

Total = df.groupby['MyColumn'].sum() print Total

这会导致以下错误:

TypeError: 'instancemethod' object has no attribute '__getitem__'

预期产量

Expected Output

我希望输出如下:

319

或者，我希望使用新的row标题为TOTAL的df进行编辑，其中包含总计:

Or alternatively, I would like df to be edited with a new row entitled TOTAL containing the total:

X MyColumn Y Z 0 A 84 13.0 69.0 1 B 76 77.0 127.0 2 C 28 69.0 16.0 3 D 28 28.0 31.0 4 E 19 20.0 85.0 5 F 84 193.0 70.0 TOTAL 319

推荐答案

您应使用 sum :

Total = df['MyColumn'].sum() print (Total) 319

然后您使用 loc 使用Series，在这种情况下，索引应设置为与您需要求和的特定列相同:

Then you use loc with Series, in that case the index should be set as the same as the specific column you need to sum:

df.loc['Total'] = pd.Series(df['MyColumn'].sum(), index = ['MyColumn']) print (df) X MyColumn Y Z 0 A 84.0 13.0 69.0 1 B 76.0 77.0 127.0 2 C 28.0 69.0 16.0 3 D 28.0 28.0 31.0 4 E 19.0 20.0 85.0 5 F 84.0 193.0 70.0 Total NaN 319.0 NaN NaN

因为如果传递标量，则将填充所有行的值:

because if you pass scalar, the values of all rows will be filled:

df.loc['Total'] = df['MyColumn'].sum() print (df) X MyColumn Y Z 0 A 84 13.0 69.0 1 B 76 77.0 127.0 2 C 28 69.0 16.0 3 D 28 28.0 31.0 4 E 19 20.0 85.0 5 F 84 193.0 70.0 Total 319 319 319.0 319.0

另两个解决方案是 at ，然后 ix 参见以下应用程序:

Two other solutions are with at, and ix see the applications below:

df.at['Total', 'MyColumn'] = df['MyColumn'].sum() print (df) X MyColumn Y Z 0 A 84.0 13.0 69.0 1 B 76.0 77.0 127.0 2 C 28.0 69.0 16.0 3 D 28.0 28.0 31.0 4 E 19.0 20.0 85.0 5 F 84.0 193.0 70.0 Total NaN 319.0 NaN NaN

df.ix['Total', 'MyColumn'] = df['MyColumn'].sum() print (df) X MyColumn Y Z 0 A 84.0 13.0 69.0 1 B 76.0 77.0 127.0 2 C 28.0 69.0 16.0 3 D 28.0 28.0 31.0 4 E 19.0 20.0 85.0 5 F 84.0 193.0 70.0 Total NaN 319.0 NaN NaN

注意:自Pandas v0.20起，已不推荐使用ix.改用loc或iloc.

Note: Since Pandas v0.20, ix has been deprecated. Use loc or iloc instead.