How can I split a character string in a dataframe into multiple columns

Question

I\'m working with a dataframe, one column of which contains values that are mostly numeric but may contain non-numeric entries. I would like to split this column into multiple

Answer 1

This does not use any packages:

transform(df,
  x1 = ifelse(grepl(" ", x), sub(" .*", "", x), NA),
  x2 = sub(".* ", "", paste(x)))

giving:

  ID     x   x1  x2
1  1 < 0.1    < 0.1
2  2   100 <NA> 100
3  3 A 2.5    A 2.5
4  4   200 <NA> 200

Answer 2

You can use separate() from tidyr

tidyr::separate(df, x, c("x1", "x2"), " ", fill = "left")
#   ID   x1  x2
# 1  1    < 0.1
# 2  2 <NA> 100
# 3  3    A 2.5
# 4  4 <NA> 200

If you absolutely need to remove the NA values, then you can do

tdy <- tidyr::separate(df, x, c("x1", "x2"), " ", fill = "left")
tdy[is.na(tdy)] <- ""

and then we have

tdy
#   ID x1  x2
# 1  1  < 0.1
# 2  2    100
# 3  3  A 2.5
# 4  4    200