Find the location of a character in string

Question

I would like to find the location of a character in a string    Say  string    the2quickbrownfoxeswere2tired   I would like the function to return 4 and 24 -- the character location of the 2s in string

User · Answer

You can make the output just 4 and 24 using unlist   unlist gregexpr pattern   2   the2quickbrownfoxeswere2tired     1   4 24

User · Answer

You could use grep as well  grep  2   strsplit string       1     4 24

User · Answer

find the position of the nth occurrence of str2 in str1 same order of parameters as Oracle SQL INSTR   returns 0 if not found  instr  lt - function str1 str2 startpos 1 n 1       aa unlist strsplit substring str1 startpos  str2       if length aa   lt  n 1   return 0       return sum nchar aa 1 n      startpos  n-1  nchar str2        instr  xxabcdefabdddfabx   ab    1  3 instr  xxabcdefabdddfabx   ab  1 3   1  15 instr  xxabcdefabdddfabx   xx  2 1   1  0

User · Answer

To only find the first locations  use lapply   with min     my string  lt - c  test1    test1test1    test1test1test1    unlist lapply gregexpr pattern    1   my string   min     gt   1  5 5 5    or the readable tidyverse form my string   gt     gregexpr pattern    1     gt     lapply min    gt     unlist     gt   1  5 5 5   To only find the last locations  use lapply   with max     unlist lapply gregexpr pattern    1   my string   max     gt   1   5 10 15    or the readable tidyverse form my string   gt     gregexpr pattern    1     gt     lapply max    gt     unlist     gt   1   5 10 15

User · Answer

You can use gregexpr   gregexpr pattern   2   the2quickbrownfoxeswere2tired       1    1   4 24 attr   match length    1  1 1 attr   useBytes    1  TRUE   or perhaps str locate all from package stringr which is a wrapper for gregexpr stringi  stri locate all  as of stringr version 1 0   library stringr  str locate all pattern   2    the2quickbrownfoxeswere2tired      1        start end  1       4   4  2      24  24   note that you could simply use stringi  library stringi  stri locate all pattern    2    the2quickbrownfoxeswere2tired   fixed   TRUE    Another option in base R would be something like  lapply strsplit x       function x  which x     2      should work  given a character vector x

User · Answer

Here s another straightforward alternative    gt  which strsplit string       1     2    1   4 24

[regex] Find the location of a character in string

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