How to split contents in a single column into two separate columns in R?

Question

I have a column in my dataframe:

Colname
20151102
19920311
20130204
>=70
60-69
20-29

I wish to split this column into two columns like:

Col1         Col2
20151102
19920311
20130204
            >=70
            60-69
            20-29

How can I achieve this result?

Answer 1

One possible solution, the idea is to use extract from tidyr . Note that the delimiter I choose (the dot) must not appear in your initial data.frame .

library(magrittr)
library(tidyr)

df$colname = df$colname %>% 
             grepl("[>=|-]+", .) %>% 
             ifelse(paste0(".", df$colname), paste0(df$colname, ".")) 

extract(df, colname, c("col1","col2"), "(.*)\\.(.*)")
#     col1  col2
#1  222222      
#2 1111111      
#3          >=70
#4         60-69
#5         20-29

Data:

df = data.frame(colname=c("222222","1111111",">=70","60-69","20-29"))

Answer 2

Without the need of any package:

df[,c("Col1", "Col2")] <- ""

isnum <- suppressWarnings(!is.na(as.numeric(df$colname)))

df$Col1[isnum] <- df$colname[isnum]
df$Col2[!isnum] <- df$colname[!isnum]

df <- df[,!(names(df) %in% "colname")]

Data:

df = data.frame(colname=c("20151102","19920311","20130204",">=70","60-69","20-29"), stringsAsFactors=FALSE)

Answer 3

Here is a single statement solution. read.pattern captures the two field types separately in the parts of the regular expression surrounded by parentheses. ( format can be omitted if the Colname column is already of class "character" . Also, if it were desired to have the first column numeric then omit the colClasses argument.)

library(gsubfn)
read.pattern(text = format(DF$Colname), pattern = "(^\\d+$)|(.*)", 
                   col.names = c("Col1", "Col2"), colClasses = "character")

giving:

      col1     col2
1 20151102         
2 19920311         
3 20130204         
4          >=70    
5          60-69   
6          20-29 

Note: Here is a visualization of the regular expression used:

(^\d+$)|(.*)

Debuggex Demo