如何在 Pandas 中复制行? [英] How can I replicate rows in Pandas?

问题描述

我的熊猫数据框如下所示:

My pandas dataframe looks like this:

   Person  ID   ZipCode   Gender
0  12345   882  38182     Female
1  32917   271  88172     Male
2  18273   552  90291     Female

我想将每一行复制 3 次，例如:

I want to replicate every row 3 times like:

   Person  ID   ZipCode   Gender
0  12345   882  38182     Female
0  12345   882  38182     Female
0  12345   882  38182     Female
1  32917   271  88172     Male
1  32917   271  88172     Male
1  32917   271  88172     Male
2  18273   552  90291     Female
2  18273   552  90291     Female
2  18273   552  90291     Female

当然，重置索引是这样的:

And of course, reset the index so it is:

0
1
2
...

我尝试了以下解决方案:

I tried solutions such as:

pd.concat([df[:5]]*3, ignore_index=True)

还有:

df.reindex(np.repeat(df.index.values, df['ID']), method='ffill')

但它们都不起作用.

推荐答案

尝试使用 np.repeat:

newdf = pd.DataFrame(np.repeat(df.values,3,axis=0))
newdf.columns = df.columns
print(newdf)

上面的代码会输出:

  Person   ID ZipCode  Gender
0  12345  882   38182  Female
1  12345  882   38182  Female
2  12345  882   38182  Female
3  32917  271   88172    Male
4  32917  271   88172    Male
5  32917  271   88172    Male
6  18273  552   90291  Female
7  18273  552   90291  Female
8  18273  552   90291  Female

np.repeat重复df的值，3次.

然后我们通过分配new_df.columns = df.columns来添加列.

Then we add the columns with assigning new_df.columns = df.columns.

您也可以在第一行指定列名，如下所示:

You could also assign the column names in the first line, like below:

newdf = pd.DataFrame(np.repeat(df.values, 3, axis=0), columns=df.columns)
print(newdf)

上面的代码也会输出:

  Person   ID ZipCode  Gender
0  12345  882   38182  Female
1  12345  882   38182  Female
2  12345  882   38182  Female
3  32917  271   88172    Male
4  32917  271   88172    Male
5  32917  271   88172    Male
6  18273  552   90291  Female
7  18273  552   90291  Female
8  18273  552   90291  Female

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