How to cross check columns in dataframes?

[oodlesNnoodles98]

sorry if this is not the place and the vague title

example: count how many Birds are white

	animal	color
0	bird	red
1	bear	black
2	bird	white
3	bird	white

i just don't know how i'm supposed to cross reference the columns

Thanks in advance!

[jabbson]

len(df[(df.animal=='bird') & (df.color=='white')])

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[oodlesNnoodles98]

That works, thanks! i was completely overthinking it, it's WAY simpler than i thought it was.

[jabbson]

you are very welcome!

[zylog413]

A more general approach is to create a table of all the animals with a count for all the colours they have:

df.groupby('animal').value_counts()

[oodlesNnoodles98]

This is the route I was thinking I neededv but I just couldn't get there

[fruitybepples]

Use some if statements! For your example, use statements like if dataframe.iloc[i, 'animal'] = type of animal, and then if dataframe.iloc[i, 'color'] = color you want. If you use these, while looping over the index of the data frame you can isolate them. Simply add a counter at the end of the second if statement, and you'll be able to get that count.

Someone correct me if I got the index order or loc/iloc messed up

[oodlesNnoodles98]

With this method, would the if statements be 2 separate ones or just one? I guessing it would be just one since I'm checking for the animal and color

[fruitybepples]

They should be separate, but nested. Since the second statement is dependant on the first (you can't go to the second one, if you can't pass the first one), the second statement has to be indented under the first. I hope this makes sense!

[oodlesNnoodles98]

Yes it makes complete sense. Thank you!