Extract left and right limit from a Series of pandas Intervals

Question

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 us

Answer 1

A simple way is to use apply() method:

    data['left'] = data['intervals'].apply(lambda x: x.left)
    data['right'] = data['intervals'].apply(lambda x: x.right)
    data

    intervals      left     right
    0   (85, 94]     85      94
    1   (95, 104]    95     104
    ...
    8   (165, 174]  165     174

Answer 2

Create an pandas.IntervalIndex from your intervals. You can then access the .left and .right attributes.

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

---

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

Answer 3

A pandas.arrays.IntervalArray, is the preferred way for storing interval data in Series-like structures.

For @coldspeed's first example, IntervalArray is basically a drop in replacement:

In [2]: pd.__version__
Out[2]: '1.1.3'

In [3]: ia = pd.arrays.IntervalArray([i1, i2, i3, i4, i5, i6, i7, i8, i9])

In [4]: df = pd.DataFrame({'intervals': ia, 'left': ia.left, 'right': ia.right})

In [5]: df
Out[5]:
    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

If you already have interval data in a Series or DataFrame, @coldspeed's second example becomes a bit more simple by accessing the array attribute:

In [6]: df = pd.DataFrame({'intervals': ia})

In [7]: df['left'] = df['intervals'].array.left

In [8]: df['right'] = df['intervals'].array.right

In [9]: df
Out[9]:
    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