How to avoid: read.table truncates numeric values beginning with 0

Question

I want to import a table (.txt file) in R with read.table(). One column in my table is an ID with nine numerals - some ids begin with a 0, other wi

Answer 1

Here is a for loop to add leading zeros to rows based on a condition. Although this is a post-hoc solution (adding leading 0's after reading the table), it worked for me so thought I'd share:

Let's take the example of a column of zip codes. All values should contain 5 digits (e.g. 01234), but R removes leading zeros (so '01234' becomes '1234'). You can add a trailing zero to all cells that contain only 4 characters with this code:

for (i in 1:nrow(df)){
  if(nchar(df$zipCode[i])<5){
    df$zipCode[i]<- paste0('0',df$zipCode[i])
  }
}