Loop for a dataframe

Question

I have a question for a possible loop. Maybe there is another solution for the problem?

Here the example of my dataframe:

Dataframe example

I want to count the values in column "to count"(always 1) if the values in column "id" are the same and write the result in column "solution?"

After that i can delete column "z" and do "unique"

I think it`s not too hard, but i do not find the right command + I got my Problems with loops :-(

Thanks for help!

In the future, please don't share your data as screenshots. It's useless that way for testing code. Read the [FAQ](http://stackoverflow.com/q/5963269/1412059) to learn better ways of sharing data. — Roland, Aug 03 '13 at 16:01
@Roland , Thanks a lot for helping me out. You saved me Weekend ! I will consider the FAQ next time ;-) — Laudl007, Aug 03 '13 at 17:43

score 1 · Answer 1 · edited Aug 03 '13 at 16:00

1

You can use ddply from plyr package [Assume mydata is your data)

library(plyr)
ddply(mydata,.(id),transform, solution=length(id))

edited Aug 03 '13 at 16:00

Jilber Urbina

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answered Aug 03 '13 at 15:59

Metrics

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Roland · Accepted Answer · 2013-08-03T16:04:57.690

1

You can do this all in one step:

library(plyr)

ddply(DF, .(id, x, y), summarise, sumcount=sum(to_count))

edited Aug 03 '13 at 16:04

answered Aug 03 '13 at 15:59

Roland

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Loop for a dataframe

2 Answers2