CODEWITHSUNDEEP
rconditional-statements
user3641630
user3641630

Reputation: 335

R-Creating a New Column Based On Positions Specified by an Existing Column

I have a dataset (df) looks like this. 

A   B   C   D   E   Position    
67  68  69  70  71   5           
20  21  22  23  24   2           
98  97  96  95  94   3           
2   5   7   9   12   5           
4   8   12  16  20   4

I am trying to create a new column (Result) where the value of result is equal to the position of the column specified in the position column for each row of the resulting column.

For example, if the row 1 of position column is 5, the Result column will have the value of 5th column of row 1.

My resulting column will look like this:

     A   B  C   D   E   Position    Result
    67  68  69  70  71   5           71
    20  21  22  23  24   2           21
    98  97  96  95  94   3           96
    2   5   7   9   12   5           12
    4   8   12  16  20   4           16

I used the following command, which does not give me what I need. It lumps all of the position column values in each row. I am unable to determine how I can get the correct result.

Any help is appreciated.

Thanks!

Upvotes: 1

Views: 147

Answers (1)

A5C1D2H2I1M1N2O1R2T1
A5C1D2H2I1M1N2O1R2T1

Reputation: 193687

Use matrix indexing to extract the values:

df[cbind(1:nrow(df), df$Position)]
# [1] 71 21 96 12 16

Assign the result in the normal way:

df$Result <- df[cbind(1:nrow(df), df$Position)]

Upvotes: 2

Related Questions