Cumsum is a MatLab, NumPy, Pandas and R function that returns the cumulative sum along different dimensions of an array.
Cumsum is a MatLab, NumPy, Pandas and R function that returns the cumulative sum along different dimensions of an array.
Questions tagged [cumsum]
799 questions
147
votes
8 answers
Pandas groupby cumulative sum
I would like to add a cumulative sum column to my Pandas dataframe so that:
name
day
no
Jack
Monday
10
Jack
Tuesday
20
Jack
Tuesday
10
Jack
Wednesday
50
Jill
Monday
40
Jill
Wednesday
110
becomes:
Jack | Monday | 10 |…
kc2819
- 1,491
- 2
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- 5
61
votes
5 answers
Calculate cumulative sum (cumsum) by group
With data frame:
df <- data.frame(id = rep(1:3, each = 5)
, hour = rep(1:5, 3)
, value = sample(1:15))
I want to add a cumulative sum column that matches the id:
df
id hour value csum
1 1 1 7 7
2 1…
Rock
- 2,827
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52
votes
4 answers
How to groupby consecutive values in pandas DataFrame
I have a column in a DataFrame with values:
[1, 1, -1, 1, -1, -1]
How can I group them like this?
[1,1] [-1] [1] [-1, -1]
Bryan Fok
- 3,277
- 2
- 31
- 59
44
votes
1 answer
Cumsum as a new column in an existing Pandas dataframe
I have a pandas dataframe defined as:
A B SUM_C
1 1 10
1 2 20
I would like to do a cumulative sum of SUM_C and add it as a new column to the same dataframe. In other words, my end goal is to have a dataframe that looks…
user1124702
- 1,015
- 4
- 12
- 22
42
votes
3 answers
Perform a reverse cumulative sum on a numpy array
Can anyone recommend a way to do a reverse cumulative sum on a numpy array?
Where 'reverse cumulative sum' is defined as below (I welcome any corrections on the name for this procedure):
if
x =…
Lee
- 29,398
- 28
- 117
- 170
35
votes
2 answers
cumsum per group in dplyr
I am starting to enjoy dplyr but I got stuck on a use case. I want to be able to apply cumsum per group in a dataframe with the package but I can't seem to get it right.
For a demo dataframe I've generated the following data:
set.seed(123)
len =…
cantdutchthis
- 31,949
- 17
- 74
- 114
31
votes
5 answers
Efficient summation in Python
I am trying to efficiently compute a summation of a summation in Python:
WolframAlpha is able to compute it too a high n value: sum of sum.
I have two approaches: a for loop method and an np.sum method. I thought the np.sum approach would be…
Adam
- 433
- 5
- 9
31
votes
1 answer
Pandas dataframe - running sum with reset
I want to calculate the running sum in a given column(without using loops, of course). The caveat is that I have this other column that specifies when to reset the running sum to the value present in that row. Best explained by the following…
Baron Yugovich
- 3,843
- 12
- 48
- 76
28
votes
3 answers
How to compute cumulative sum of previous N rows in pandas?
I am working with pandas, but I don't have so much experience. I have the following DataFrame:
A
0 NaN
1 0.00
2 0.00
3 3.33
4 10.21
5 6.67
6 7.00
7 8.27
8 6.07
9 2.17
10 3.38
11 …
lmiguelvargasf
- 63,191
- 45
- 217
- 228
26
votes
5 answers
What is the inverse of the numpy cumsum function?
If I have z = cumsum( [ 0, 1, 2, 6, 9 ] ), which gives me z = [ 0, 1, 3, 9, 18 ], how can I get back to the original array [ 0, 1, 2, 6, 9 ] ?
scottlittle
- 18,866
- 8
- 51
- 70
25
votes
7 answers
Compute the cumulative sum of a list until a zero appears
I have a (long) list in which zeros and ones appear at random:
list_a = [1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 1]
I want to get the list_b
sum of the list up to where 0 appears
where 0 appears, retain 0 in the list
list_b = [1, 2, 3, 0, 1, 2, 0, 1, 0,…
Hiroyuki Taniichi
- 426
- 6
- 11
22
votes
5 answers
Cumsum reset at NaN
If I have a pandas.core.series.Series named ts of either 1's or NaN's like this:
3382 NaN
3381 NaN
...
3369 NaN
3368 NaN
...
15 1
10 NaN
11 1
12 1
13 1
9 NaN
8 NaN
7 NaN
6 NaN
3 NaN
4 1
5 1
2 …
working4coins
- 1,997
- 3
- 22
- 30
20
votes
5 answers
Conditional cumsum with reset
I have a data frame, the data frame is already sorted as needed, but now I will like to "slice it" in groups.
This groups should have a max cumulative value of 10. When the cumulative value is > 10, it should reset the cumulative sum and start over…
Iair Kleiman
- 221
- 2
- 8
20
votes
2 answers
generalized cumulative functions in NumPy/SciPy?
Is there a function in numpy or scipy (or some other library) that generalizes the idea of cumsum and cumprod to arbitrary function. For example, consider the (theoretical) function
cumf( func, array)
func is a function that accepts two floats,…
Cam.Davidson.Pilon
- 1,606
- 1
- 17
- 31
18
votes
3 answers
Calculating cumulative returns with pandas dataframe
I have this dataframe
Poloniex_DOGE_BTC Poloniex_XMR_BTC Daily_rets perc_ret
172 0.006085 -0.000839 0.003309 0
173 0.006229 0.002111 0.005135 0
174 0.000000 -0.001651 0.004203 0
175 0.000000 0.007743 0.005313 …
David Hancock
- 1,063
- 4
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- 28