pandas restart cumsum every time the value is zero
Question:
so I have a series, I want to cumsum, but start over every time I hit a 0, somthing like this:
orig
wanted result
0
0
0
1
1
1
2
1
2
3
1
3
4
1
4
5
1
5
6
1
6
7
0
0
8
1
1
9
1
2
10
1
3
11
0
0
12
1
1
13
1
2
14
1
3
15
1
4
16
1
5
17
1
6
any ideas? (pandas, pure python, other)
Answers:
Use df['orig'].eq(0).cumsum() to generate groups starting on each 0, then cumcount to get the increasing values:
df['result'] = df.groupby(df['orig'].eq(0).cumsum()).cumcount()
output:
orig wanted result result
0 0 0 0
1 1 1 1
2 1 2 2
3 1 3 3
4 1 4 4
5 1 5 5
6 1 6 6
7 0 0 0
8 1 1 1
9 1 2 2
10 1 3 3
11 0 0 0
12 1 1 1
13 1 2 2
14 1 3 3
15 1 4 4
16 1 5 5
17 1 6 6
Intermediate:
df['orig'].eq(0).cumsum()
0 1
1 1
2 1
3 1
4 1
5 1
6 1
7 2
8 2
9 2
10 2
11 3
12 3
13 3
14 3
15 3
16 3
17 3
Name: orig, dtype: int64
import pandas as pd
condition = df.Orig.eq(0)
df['reset'] = condition.cumsum()
so I have a series, I want to cumsum, but start over every time I hit a 0, somthing like this:
| orig | wanted result | |
|---|---|---|
| 0 | 0 | 0 |
| 1 | 1 | 1 |
| 2 | 1 | 2 |
| 3 | 1 | 3 |
| 4 | 1 | 4 |
| 5 | 1 | 5 |
| 6 | 1 | 6 |
| 7 | 0 | 0 |
| 8 | 1 | 1 |
| 9 | 1 | 2 |
| 10 | 1 | 3 |
| 11 | 0 | 0 |
| 12 | 1 | 1 |
| 13 | 1 | 2 |
| 14 | 1 | 3 |
| 15 | 1 | 4 |
| 16 | 1 | 5 |
| 17 | 1 | 6 |
any ideas? (pandas, pure python, other)
Use df['orig'].eq(0).cumsum() to generate groups starting on each 0, then cumcount to get the increasing values:
df['result'] = df.groupby(df['orig'].eq(0).cumsum()).cumcount()
output:
orig wanted result result
0 0 0 0
1 1 1 1
2 1 2 2
3 1 3 3
4 1 4 4
5 1 5 5
6 1 6 6
7 0 0 0
8 1 1 1
9 1 2 2
10 1 3 3
11 0 0 0
12 1 1 1
13 1 2 2
14 1 3 3
15 1 4 4
16 1 5 5
17 1 6 6
Intermediate:
df['orig'].eq(0).cumsum()
0 1
1 1
2 1
3 1
4 1
5 1
6 1
7 2
8 2
9 2
10 2
11 3
12 3
13 3
14 3
15 3
16 3
17 3
Name: orig, dtype: int64
import pandas as pd
condition = df.Orig.eq(0)
df['reset'] = condition.cumsum()