How to remove last n characters from every element in the R vector

Question

I am very new to R  and I could not find a simple example online of how to remove the last n characters from every element of a vector  array     I come from a Java background  so what I would like to do is to iterate over every element of a data and remove the last 3 characters from every element   How would you go about it

User · Answer

Here s a way with gsub   cs  lt - c  foo bar   bar foo   apple   beer   gsub    3         cs     1   foo    bar    ap     b

User · Answer

Although this is mostly the same with the answer by  nfmcclure  I prefer using stringr package as it provdies a set of functions whose names are most consistent and descriptive than those in base R  in fact I always google for  how to get the number of characters in R  as I can t remember the name nchar       library stringr  str sub iris Species  end -4   or  str sub iris Species  1  str length iris Species -3    This removes the last 3 characters from each value at Species column

User · Answer

Similar to  Matthew Plourde using gsub   However  using a pattern that will trim to zero characters i e  return    if the original string is shorter than the number of characters to cut   cs  lt - c  foo bar   bar foo   apple   beer   so   a   gsub    0 3         cs     1   foo    bar    ap     b                Difference is   0 3  quantifier indicates 0 to 3 matches  whereas  3  requires exactly 3 matches otherwise no match is found in which case gsub returns the original  unmodified string   N B  using   3  would be equivalent to  0 3   I simply prefer the latter notation   See here for more information on regex quantifiers  https   www regular-expressions info refrepeat html

User · Answer

Here is an example of what I would do   I hope it s what you re looking for   char array   c  foo bar   bar foo   apple   beer   a   data frame  data  char array  data2  1 4  a data   substr a data 1 nchar a data -3    a should now contain     data data2 1 foo  1 2 bar  2 3   ap 3 4    b 4

User · Answer

The same may be achieved with the stringi package   library  stringi   char array  lt - c  foo bar   bar foo   apple   beer   a  lt - data frame  data  char array   data2  1 4   a data  lt - stri sub a data  1  -4     from the first to the last but 4th char     1   foo    bar    ap     b

[r] How to remove last n characters from every element in the R vector

Examples related to r

Examples related to string