CODEWITHSUNDEEP
pythonpandasnumpydataframerow
Pablo
Pablo

Reputation: 99

Python dataframe sume iterative

I have a dataframe like this:

t; value
5; 10   
4; 0
3; 2
2; 0
1; 1

What I want is to sum iterative over the columns in row "values" so that I get this:

t; value; sum
5; 10;    13
4; 0;     3
3; 2;     3
2; 0;     1
1; 1;     1

How I can do this in python with dataframe?

t = time

Upvotes: 1

Views: 57

Answers (1)

DYZ
DYZ

Reputation: 57033

There is a function cumsum that calculates the cumulative sum from the top to the bottom. Reverse the dataframe, then calculate the sum:

df['sum'] = df.loc[::-1, 'value'].cumsum()
#   t   value  sum
#0  5      10   13
#1  4       0    3
#2  3       2    3
#3  2       0    1
#4  1       1    1

Upvotes: 2

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