Use a 'for' loop for the 'aggregate' command?

Question

I've got a data frame as so,

Treatment Type  Numerical Value
1          A          3
1          B          2
1          A          8
1          B          7
2          B          4
2          B          1
2          A          2
2          A          2

I want to make a table of means for each type and treatments.

Using aggregate, I have: aggregate(df[,3], list(Treatment) ,mean) which gives me the means for each treatment but not separated by type too. I was thinking this could be rectified by a for-loop.

Note: This is just a subset of the data, and the list of numerical values is hundreds for each type and treatment.

```aggregate(`Numerical Value` ~ Treatment + Type, df, mean)```? Haven't tested but should work — David Arenburg, Oct 29 '15 at 19:47
Yeah works for the subset, but for some reason when I apply to the whole set I get the error: `Error in eval(predvars, data, env) : numeric 'envir' arg not of length one' — E1993, Oct 29 '15 at 19:59

score 0 · Accepted Answer · edited Oct 29 '15 at 19:56

0

Since I don't have repu to comment:

aggregate(df, list(Treatment,Type), mean)

edited Oct 29 '15 at 19:56

TayTay

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answered Oct 29 '15 at 19:52

Bg1850

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But I've already commented – David Arenburg Oct 29 '15 at 20:02
I did not see your comment when I answered ,I can take down the answer if thats the norm – Bg1850 Oct 29 '15 at 20:07
You don't need to *take down anything*, I'm just referring to the title of the answer. – David Arenburg Oct 29 '15 at 20:08
I meant that If I had repu to comment i would not have answered it – Bg1850 Oct 29 '15 at 20:09
@E1993 if this worked for you ,perhaps you could accept this answer :) – Bg1850 Oct 29 '15 at 20:12

Use a 'for' loop for the 'aggregate' command?

1 Answers1