digitalmars.D.learn - allocating an array in an associative array
- Dominic Jones (9/9) Feb 09 2011 Hello,
- Steven Schveighoffer (16/24) Feb 09 2011 Try using the in operator:
Hello, I want to allocate the "int[]" array for a particular key in int[][string] list; by doing list[key].length = list[key].length + 1; but it does not work. I get an array bounds error. I am using gdc 4.3.5. Any suggestions? Thank you, Dominic Jones
Feb 09 2011
On Wed, 09 Feb 2011 07:58:12 -0500, Dominic Jones <dominic.jones qmul.ac.uk> wrote:Hello, I want to allocate the "int[]" array for a particular key in int[][string] list; by doing list[key].length = list[key].length + 1; but it does not work. I get an array bounds error. I am using gdc 4.3.5. Any suggestions?Try using the in operator: if(auto arr = key in list) // arr is now type int[]* { (*arr).length = (*arr).length + 1; } else list[key] = new int[1]; // or larger if desired It incurs a double lookup when the key doesn't exist yet, but I'm not sure you can do any better (unless you know ahead of time the key is not in the AA). The issue is you are looking up list[key] without it existing, that throws the array bounds. The in check in my code checks to see if it is present first before doing anything. If they key is present, then there's only a single lookup. -Steve
Feb 09 2011