从一系列 pandas 间隔中提取左右限制 [英] Extract left and right limit from a Series of pandas Intervals

问题描述

我想获取具有熊猫间隔的列的间隔边距，并将它们写在"left"，"right"列中.Iterrows不起作用(文档说它不会用于写入数据)，而且无论如何它都不是更好的解决方案.

I want to get interval margins of a column with pandas intervals and write them in columns 'left', 'right'. Iterrows does not work (documentation says it would not be use for writing data) and, anyway it would not be the better solution.

import pandas as pd

i1 = pd.Interval(left=85, right=94)
i2 = pd.Interval(left=95, right=104)
i3 = pd.Interval(left=105, right=114)
i4 = pd.Interval(left=115, right=124)
i5 = pd.Interval(left=125, right=134)
i6 = pd.Interval(left=135, right=144)
i7 = pd.Interval(left=145, right=154)
i8 = pd.Interval(left=155, right=164)
i9 = pd.Interval(left=165, right=174)

data = pd.DataFrame(
    {
    "intervals":[i1,i2,i3,i4,i5,i6,i7,i8,i9],
    "left"     :[0,0,0,0,0,0,0,0,0],
    "right"    :[0,0,0,0,0,0,0,0,0]
    },
    index=[0,1,2,3,4,5,6,7,8]
)

#this is not working (has no effect):
for index, row in data.iterrows():
    print(row.intervals.left, row.intervals.right)
    row.left = row.intervals.left
    row.right = row.intervals.right

我们如何做类似的事情:

How can we do something like:

data['left']=data['intervals'].left

data['right']=data['intervals'].right

谢谢！

推荐答案

创建 pandas.IntervalIndex .然后，您可以访问 .left 和 .right 属性.

import pandas as pd

idx = pd.IntervalIndex([i1, i2, i3, i4, i5, i6, i7, i8, i9])  
pd.DataFrame({'intervals': idx, 'left': idx.left, 'right': idx.right})

    intervals  left  right
0    (85, 94]    85     94
1   (95, 104]    95    104
2  (105, 114]   105    114
3  (115, 124]   115    124
4  (125, 134]   125    134
5  (135, 144]   135    144
6  (145, 154]   145    154
7  (155, 164]   155    164
8  (165, 174]   165    174

---

另一种选择是使用 map 和 operator.attrgetter (看起来不错，没有 lambda ...):

---

Another option is using map and operator.attrgetter (look ma, no lambda...):

from operator import attrgetter

df['left'] = df['intervals'].map(attrgetter('left'))
df['right'] = df['intervals'].map(attrgetter('right'))

df
    intervals left right
0    (85, 94]   85    94
1   (95, 104]   95   104
2  (105, 114]  105   114
3  (115, 124]  115   124
4  (125, 134]  125   134
5  (135, 144]  135   144
6  (145, 154]  145   154
7  (155, 164]  155   164
8  (165, 174]  165   174

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