pandas 将列转换为总数的百分比 [英] pandas convert columns to percentages of the totals

问题描述

我有一个数据框，其中包含4列ID和3个类别，结果属于

I have a dataframe with 4 columns an ID and three categories that results fell into

  <80% 80-90 >90
id
1   2     4    4
2   3     6    1
3   7     0    3

我想将其转换为百分比，即:

I would like to convert it to percentages ie:

   <80% 80-90 >90
id
1   20%   40%  40%
2   30%   60%  10%
3   70%    0%  30%

这似乎应该在熊猫的能力范围之内，但我只是想不通.

this seems like it should be within pandas capabilities but I just can't figure it out.

提前谢谢！

推荐答案

您可以使用基本的熊猫运算符.div和.sum，并使用axis参数来确保计算按照您希望的方式进行:

You can do this using basic pandas operators .div and .sum, using the axis argument to make sure the calculations happen the way you want:

cols = ['<80%', '80-90', '>90']
df[cols] = df[cols].div(df[cols].sum(axis=1), axis=0).multiply(100)

• 计算每列的总和(df[cols].sum(axis=1). axis=1使求和发生在各行中，而不是在各列下进行.
• 将数据帧除以所得的序列(df[cols].div(df[cols].sum(axis=1), axis=0). axis=0使划分跨列进行.
• 最后，将结果乘以100，以便它们是0到100之间的百分比，而不是0到1之间的比例(或者您可以跳过此步骤并将它们存储为比例).
• Calculate the sum of each column (df[cols].sum(axis=1). axis=1 makes the summation occur across the rows, rather than down the columns.
• Divide the dataframe by the resulting series (df[cols].div(df[cols].sum(axis=1), axis=0). axis=0 makes the division happen across the columns.
• To finish, multiply the results by 100 so they are percentages between 0 and 100 instead of proportions between 0 and 1 (or you can skip this step and store them as proportions).

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