Pascal - split string to array by each character

Question

I'm trying to find solution, how can I split string like this:

abkgwvc

to array by character? Expected output is:

array[0] = a
array[3] = g
...

any idea?

Solution:

for i := 0 to length(string) do
begin
    array[i] = copy(string, i, 1);
end;

this page might help you math.uww.edu/~harrisb/courses/cs171/strings.html — Myko Huff
– Myko Huff, Commented Nov 4, 2013 at 19:14
Your solution is mostly correct, except that your destination array is 0-based and the 3rd parameter to Copy is the number of characters to copy, not the final index. — afrazier
– afrazier, Commented Nov 4, 2013 at 19:18
Strings use a 1-based index in Turbo Pascal. Assuming your array is zero-based, you can actually just do array[i] = string[i+1]; in your loop body and then correct the for to go only up to length(string)-1. — 500 - Internal Server Error
– 500 - Internal Server Error, Commented Nov 4, 2013 at 19:49

Ken White · Accepted Answer · 2013-11-04 23:23:09Z

7

A string can be accessed as an array of characters directly, so there's no need to use Copy. The example below is based on versions of Delphi/Lazarus that support dynamic arrays, but you can use an old-style fixed length array (Arr: array[..] of Char) the same way; just remove the SetLength call and change the declaration to the right array type.

var
  Str: string;
  Arr: array of Char;
  i: Integer;
  Len: Integer;
begin
  Str := 'abkgwvc';
  Len := Length(Str);
  SetLength(arr, Len);

  // Dynamic arrays are 0-based indexing, while
  // strings are 1 based. We need to subtract 1
  // from the array index.
  for i := 1 to Len do
    Arr[i - 1] := Str[i];  
end;

(Of course, if you're not using dynamic arrays, it's not clear why you'd need a separate array in the first place; you can just access the string char-by-char directly.)

answered Nov 4, 2013 at 23:23

Ken White

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2 Comments

Marco van de Voort Over a year ago

In TP he is most likely to use shortstrings, which are the default "string" there. No setlength, length assignment is s[0]:=chr(len);

Ken White Over a year ago

@Marco: The SetLength is being used on a dynamic array, not a string, and I covered older fixed length arrays in the first paragraph. :) Setting the zero byte to a value doesn't set an array's size, only that of a shortstring. Length(s) applies to both ShortString and modern strings.

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