如何在一次或多次调用中为多个变量重塑数据帧，从宽到长? [英] How to reshape dataframe, wide to long, for several variables in one or several calls?

问题描述

我一直无法将下面的数据框改造成长格式:

I've been unable to reshape the below dataframe into the long format:

  df = pd.DataFrame({'id': [66602088802, 85002620928],
     't1': ['car', 'house'],
     't1_pct': [0.46, 0.51],
     't1_valid': [True, True],
     't2': ['bike', 'car'],
     't2_pct': [0.15, 0.07],
     't2_valid': [True, True],
     't3': ['car', 'toy'],
     't3_pct': [0.06, 0.07],
     't3_valid': [False, False]})

    id               t1     t1_pct  t1_valid t2  t2_pct t2_valid    t3  t3_pct  t3_valid
0   66602088802     car     0.46    True    bike    0.15    True    car     0.06    False
1   85002620928     house   0.51    True    car     0.07    True    toy     0.07    False

我想要的结果如下.我尝试使用 pandas.wide_to_long() 但到目前为止没有运气.提前致谢.

My desired outcome is below. I've attempted to use pandas.wide_to_long() but so far no luck. Thanks in advance.

    id         test  value     pct     valid
66602088802    1      car     0.46     True
85002620928    1      house   0.51     True
66602088802    2      bike    0.15     True
85002620928    2      car     0.07     True
66602088802    3      car     0.06     False
85002620928    3      toy     0.07     False

提前致谢.

熊猫 0.23.4

蟒蛇 3.7.1

推荐答案

您可以使用 wide_to_long;问题只是您的列名需要稍微更改一下，以便存根名称是 ['pct', 'valid', 'value']，而不是 t#.

You can use wide_to_long; the issue is just that your column names need to be changed a bit, so that the stubnames are ['pct', 'valid', 'value'], and not t#.

import pandas as pd
import numpy as np

# Reverse order of words around '_'
df.columns = ['_'.join(x.split('_')[::-1]) for x in df.columns]
# Add prefix for other stubs
df = df.rename(columns= dict((f't{i}', f'value_t{i}') for i in np.arange(1,4,1)))

pd.wide_to_long(df, stubnames=['pct', 'valid', 'value'], 
                i='id', j='test', suffix='.*', sep='_').reset_index()

输出:

            id test   pct  valid  value
0  66602088802   t1  0.46   True    car
1  85002620928   t1  0.51   True  house
2  66602088802   t2  0.15   True   bike
3  85002620928   t2  0.07   True    car
4  66602088802   t3  0.06  False    car
5  85002620928   t3  0.07  False    toy

这篇关于如何在一次或多次调用中为多个变量重塑数据帧，从宽到长?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！