pandas 插入备用空白行 [英] Pandas insert alternate blank rows
本文介绍了 pandas 插入备用空白行的处理方法,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
给出以下数据框:
import pandas as pd
import numpy as np
df1=pd.DataFrame({'A':['a','b','c','d'],
'B':['d',np.nan,'c','f']})
df1
A B
0 a d
1 b NaN
2 c c
3 d f
我想在每行之前插入空白行. 理想的结果是:
I'd like to insert blank rows before each row. The desired result is:
A B
0 NaN NaN
1 a d
2 NaN NaN
3 b NaN
4 NaN NaN
5 c c
6 NaN NaN
7 d f
实际上,我有很多行.
提前谢谢!
推荐答案
使用numpy和pd.DataFrame
def pir(df):
nans = np.where(np.empty_like(df.values), np.nan, np.nan)
data = np.hstack([nans, df.values]).reshape(-1, df.shape[1])
return pd.DataFrame(data, columns=df.columns)
pir(df1)
代码
Code
def banana(df):
df1 = df.set_index(np.arange(1, 2*len(df)+1, 2))
df2 = pd.DataFrame(index=range(0, 2*len(df1), 2), columns=df1.columns)
return pd.concat([df1, df2]).sort_index()
def anton(df):
df = df.set_index(np.arange(1, 2*len(df)+1, 2))
return df.reindex(index=range(2*len(df)))
def pir(df):
nans = np.where(np.empty_like(df.values), np.nan, np.nan)
data = np.hstack([nans, df.values]).reshape(-1, df.shape[1])
return pd.DataFrame(data, columns=df.columns)
结果
Results
pd.concat([f(df1) for f in [banana, anton, pir]],
axis=1, keys=['banana', 'anton', 'pir'])
时间
Timing
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