[R] Creating binary variable depending on strings of two dataframes

[Pete Pete]

Gabor Grothendieck wrote:
> 
> On Tue, Dec 7, 2010 at 11:30 AM, Pete Pete <noxyport at gmail.com>
> wrote:
>>
>> Hi,
>> consider the following two dataframes:
>> x1=c("232","3454","3455","342","13")
>> x2=c("1","1","1","0","0")
>> data1=data.frame(x1,x2)
>>
>> y1=c("232","232","3454","3454","3455","342","13","13","13","13")
>> y2=c("E1","F3","F5","E1","E2","H4","F8","G3","E1","H2")
>> data2=data.frame(y1,y2)
>>
>> I need a new column in dataframe data1 (x3), which is either 0 or 1
>> depending if the value "E1" in y2 of data2 is true while x1=y1. The
>> result
>> of data1 should look like this:
>>   x1     x2 x3
>> 1 232   1   1
>> 2 3454 1   1
>> 3 3455 1   0
>> 4 342   0   0
>> 5 13     0   1
>>
>> I think a SQL command could help me but I am too inexperienced with it to
>> get there.
>>
> 
> Try this:
> 
>> library(sqldf)
>> sqldf("select x1, x2, max(y2 = 'E1') x3 from data1 d1 left join data2 d2
>> on (x1 = y1) group by x1, x2 order by d1.rowid")
>     x1 x2 x3
> 1  232  1  1
> 2 3454  1  1
> 3 3455  1  0
> 4  342  0  0
> 5   13  0  1
> 
> 
> -- 
> Statistics & Software Consulting
> GKX Group, GKX Associates Inc.
> tel: 1-877-GKX-GROUP
> email: ggrothendieck at gmail.com
> 
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That works pretty cool but I need to automate this a bit more. Consider the
following example:

list1=c("A01","B04","A64","G84","F19")

x1=c("232","3454","3455","342","13")
x2=c("1","1","1","0","0")
data1=data.frame(x1,x2)

y1=c("232","232","3454","3454","3455","342","13","13","13","13")
y2=c("E13","B04","F19","A64","E22","H44","F68","G84","F19","A01")
data2=data.frame(y1,y2)

I want now to creat a loop, which creates for every value in list1 a new
binary variable in data1. Result should look like:
x1	x2	A01	B04	A64	G84	F19
232	1	0	1	0	0	0
3454	1	0	0	1	0	1
3455	1	0	0	0	0	0
342	0	0	0	0	0	0
13	0	1	0	0	1	1

Thanks!


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