在 pandas 中将行拆分为多行 [英] Split row into multiple rows in pandas

问题描述

我有一个DataFrame，其格式如下(简化)

I have a DataFrame with a format like this (simplified)

a  b  43
a  c  22

我希望通过以下方式对此进行分解.

I would like this to be split up in the following way.

a  b  20
a  b  20
a  b  1
a  b  1
a  b  1
a  c  20
a  c  1
a  c  1

在这里，行数除以20，然后剩下的行数也一样.我有一个解决方案，基本上可以对行进行迭代并填充字典，然后可以将其转换回Dataframe，但我想知道是否有更好的解决方案.

Where I have as many rows as the number divides by 20, and then as many rows as the remainder. I have a solution that basically iterates over the rows and fills up a dictionary which can then be converted back to Dataframe but I was wondering if there is a better solution.

推荐答案

您可以先对模数使用地板分位数，然后通过constructor与DataFrame. org/doc/numpy/reference/generated/numpy.repeat.html"rel =" nofollow noreferrer> numpy.repeat .

You can use floor divison with modulo first and then create new DataFrame by constructor with numpy.repeat.

最近需要 numpy.concatenate ，其中list comprehension表示C:

a,b = df.C // 20, df.C % 20
#print (a, b)

cols = ['A','B']
df = pd.DataFrame({x: np.repeat(df[x], a + b) for x in cols})
df['C'] = np.concatenate([[20] * x + [1] * y for x,y in zip(a,b)])
print (df)
   A  B   C
0  a  b  20
0  a  b  20
0  a  b   1
0  a  b   1
0  a  b   1
1  a  c  20
1  a  c   1
1  a  c   1

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