CODEWITHSUNDEEP
r
Justin
Justin

Reputation: 47

R - Select and return column value based on value in another column

I'd like to select and return a column value contained within one of a subset of columns, based on the value in another column.

Specifically, I'd like to create a new variable ("NEWE") by selecting the value in RE when the MAX variable = "RP" and by selecting the value in IE when the MAX variable = "IP".

Of note, I am working with a data table of ~160 columns and ~70,000 rows (I am noting the existence of additional columns in my example by including V1-V9).

Have:

V1  …   V9  RE  IE  MAX
4   …   3   3   4   RP  
6   …   6   3   2   IP  
2   …   2   1   2   IP  
6   …   2   2   3   RP  
.   .   .   .   .   .
.   .   .   .   .   .   
.   .   .   .   .   .

And the data set I would like:

V1  …   V9  RE  IE  MAX NEWE
4   …   3   3   4   RP  3
6   …   6   3   2   IP  2
2   …   2   1   2   IP  2
6   …   2   2   3   RP  2
.   .   .   .   .   .   .
.   .   .   .   .   .   .
.   .   .   .   .   .   .

Thanks in advance for your help!

Upvotes: 2

Views: 3242

Answers (1)

joel.wilson
joel.wilson

Reputation: 8413

data$NEWE <- ifelse(data$MAX == "RP", data$RE, ifelse(data$MAX == "RP",data$IE, "value if both doesn't satify"))

if its either of RP and IP always!

data$NEWE <- ifelse(data$MAX == "RP", data$RE , data$IE)

for your case : its a simple extension of ifelse - (to avoid typo prefer using with())

data$NEWE <- with(data, ifelse(MAX == "RP", RE,
                               ifelse(MAX == "IP",IE, 
                                     ifelse(MAX == "AP", AE,
                                           ifelse(MAX == "SP", SE,
                                                  ifelse(MAX == "EP",EE,
                                                         ifelse(MAX == "CP", CE, NA)))))))

Upvotes: 4

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