A small tip about R — Transform the variable

For example:

temp <- data.frame(char = c("1", "2", "2", "2", "3", "3", "4", "4", "5"))

I want to have a variable to order my character between different numbers, Confusing?

Like this: 1 1 2 3 1 2 1 2 1

How can we create the variable like that?

Just two steps:

• First of all, compute how many every same char?

library(plyr)

temp2 <- ddply(temp, "char", nrow)

temp2 

##   char V1
## 1    1  1
## 2    2  3
## 3    3  2
## 4    4  2
## 5    5  1

• Second, generate sequence.

temp$new_variable <- unlist(lapply(temp2$V1, function(x) seq(length.out = x)))

temp 

##   char new_variable
## 1    1            1
## 2    2            1
## 3    2            2
## 4    2            3
## 5    3            1
## 6    3            2
## 7    4            1
## 8    4            2
## 9    5            1

Why I do this?

Just for plot by ggplot2.

Welcome your advice and suggestion!

Just record, this article was posted at linkedin, and have 23 views to November 2021.