Find the last offset in a string using Applescript
Alec Jacobson
July 29, 2009
Applescript has famously awkward, clumsy and insufficient string operations. I set about trying to extract the base address of a url (or file path) with applescript (by the way ruby provides this with the method File.dirname). Applescript provides offset of as in the offset of "e" in "hello" is 2 (remember Applescript is 1-indexed). There is no easy equivalent to find the last occurrence in a string, the last offset. Here are my two solutions.
Solution One:
on last_offset(the_text, char)
try
set i to 1
set last_occurrence to 0
repeat count of the_text times
if item i of the_text as string = char then
set last_occurrence to i
end if
set i to i + 1
end repeat
on error
return 0
end try
return last_occurrence
end last_offset
This is really Intro to Computer Programming 101 feeling. I return 0 if something goes wrong or there are no matches like the way offset of returns 0 for no match.
Solution Two:
on last_offset(the_text, char)
try
set len to count of the_text
set reversed to reverse of characters of the_text as string
set last_occurrence to len - (offset of char in reversed) + 1
if last_occurrence > len then
return 0
end if
on error
return 0
end try
return last_occurrence
end last_offset
It doesn't seem like there's any reason why one of these is faster than the other.