问题
I wanted to merge to dataset by a variable ICPSR, but since the ICPSR was factor I had to change it to numeric variable. So I did as.numeric and after doing that, my ICPSR has been changed to a totally different values. I googled and found I need to use as.numeric(level(dv$ICPSR)). But it only turns out unique values not every value. So I was wondering how can I preserve every value and change it to merge-able numeric values.
Thanks in advance!
ICPSR session dv
1:1 15245 103 0.75
1:2 13003 103 0.00
1:3 14620 103 0.25
1:4 29105 103 0.00
1:5 29104 103 0.00
1:6 14414 103 0.25
dv$ICPSR<-as.numeric(dv$ICPSR)
head(dv)
ICPSR session dv
1:1 202 103 0.75
1:2 27 103 0.00
1:3 85 103 0.25
1:4 281 103 0.00
1:5 280 103 0.00
1:6 68 103 0.25
回答1:
dv$ICPSR <- as.numeric(as.character(dv$ICPSR))
Transform your factor to a character vector before transforming it into a numeric vector.
来源：https://stackoverflow.com/questions/20538084/how-to-convert-a-factor-variable-to-numeric-while-preserving-the-numbers-in-r