Characters and Strings

• Jenny Bryan’s Data analysis 2: vectors (scroll down)
• regular expressions
• tidytext: Julia Silge & David Robinson | github | blog

Sometimes one may want to change names of columns in a table. Here is what might seem like a logical approach, but it is in fact difficult to read, awkward and repetitive, and slow.

new_names=list()
l=1
for(n in colnames(x)){
      ifelse((l<10), (colnames(x)[l]=c(paste0('Otu000',c(l)))), (colnames(x)[l]=c(paste0('Otu00',c(l))))) 
      new_names=append(new_names, colnames(x)[l])
      l=l+1
}

Here is an improved version:

new_names <- paste0("Otu", stringr::str_pad(seq_along(colnames(x)), 4, pad="0"))

It might be helpful to work up the full example, showing original code and improved version.

• Andrew Steinberger code