How can I add the values in the dataset together in Python?

Question

I am trying to add values together for each year in my dataset.

The dataframe looks like..

I'd like to add the values in NUMBER OF MOSQUITOES column, collect them in the year to which it belongs.

For example,

2007 395
2008 154
2009 353
...
...
...

Which methods in pandas or numpy can I use?

Thank you for your help in advance

Thank you a lot! I can think of it now because of your answer. I just use `df.groupby('SEASON YEAR').sum()`. Am I correct? — Liu Bei, Aug 01 '18 at 20:57

score 1 · Answer 1 · answered Aug 01 '18 at 20:57

1

If I'm understanding correctly, you want to sum the number of mosquitoes in every year. If that's the case, you can use groupby.sum(), like this:

df.groupby(['SEASON YEAR'], as_index=False).sum()

I'm not sure if that's what you're looking for, tell me otherwise.

answered Aug 01 '18 at 20:57

Juan C

Thank you very much, sir. This would be another way to sum them. Very appreciated by your help. – Liu Bei Aug 01 '18 at 21:02

score 1 · Answer 2 · answered Aug 01 '18 at 20:57

1

You can simply do groupby and sum:

df.groupby("SEASON YEAR").sum()["NUMBER OF MOSQUITOES"]

answered Aug 01 '18 at 20:57

TYZ

2 Answers2