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  100
3  3 A 2.5    A 2.5
4  4   200  200