Pandas datafram add column with line values depending on cumulative sum from existing column-CodePudding

I´m stupid and new to everything,

I want to create a new column with values that depends on the cumulative sum with a condition from an existing column and when the condition is reached the cumulative sum should start over from zero on the existing line.

For example, from this existing dataframe I want to create a new column that "tags" each line with the same tag depending on that the cumulative sum of the line with previous rows is less or equal to 80 (condition). When the condition is met the counter should start over from zero again.:

Ops	Values
First	20
Second	10
Third	35
Fourth	15
Fith	70
Sixth	15
Seventh	32
Eighth	32
Ninth	32
...	...

I want to acheive this:

Ops	Values	New column
First	20	Stn 1
Second	10	Stn 1
Third	35	Stn 1
Fourth	15	Stn 1
Fith	70	Stn 2
Sixth	15	Stn 3
Seventh	65	Stn 3
Eighth	80	Stn 4
Ninth	32	Stn 5
...	...	...

Unfortunately, I have no idea how to do this and I didn't find the answer somewhere else. Could someone give me a hint?

CodePudding user response：

You can divide by 80 and round up to get group.

df['New column'] = 'Stn '   np.ceil(df['Values'].cumsum().div(80)).astype(int).astype(str)

print(df)

       Ops  Values New column
0    First      20      Stn 1
1   Second      10      Stn 1
2    Third      35      Stn 1
3   Fourth      15      Stn 1
4     Fith      70      Stn 2
5    Sixth      15      Stn 3
6  Seventh      65      Stn 3
7   Eighth      80      Stn 4
8    Ninth      32      Stn 5