Delete All Keys From Associative Array

Part of ArraysCategory

Description

Show a couple ways that all keys can be removed from an associate array.

Example

/* inspired from: http://www.digitalmars.com/pnews/read.php?server=news.digitalmars.com&group=digitalmars.D&artnum=4199 */

void main()
{
    char[][char[]] aA;
    printf("Fill in the array.\n");
    aA["a"] = "Apple";
    aA["b"] = "Book";
    aA["c"] = "Car";

    checkArray(aA);


    /* Clearing method from http://www.digitalmars.com/pnews/read.php?server=news.digitalmars.com&group=digitalmars.D&artnum=4201 */

    printf("Clear out the items (implementation-dependent).\n");
    aA = null; 

    checkArray(aA);


    printf("\nFill in the array, again.\n");
    aA["a"] = "Apple";
    aA["b"] = "Book";
    aA["c"] = "Car";

    checkArray(aA);


    /* Clearing method from http://www.digitalmars.com/pnews/read.php?server=news.digitalmars.com&group=digitalmars.D&artnum=4202 */
    /* Updated to reflect addition of 'remove' method */

    printf("Removes it from the hash.\n");
    foreach(char[] key; aA.keys)
      aA.remove(key);  
        
    checkArray(aA);
}


void checkArray(char[][char[]] assocArr)
{
    printf("%d\t", assocArr.length);

    if("a" in assocArr)
        printf("yes 'a'\t");
    else
        printf("no 'a'\t");

    if("b" in assocArr)
        printf("yes 'b'\t");
    else
        printf("no 'b'\t");
    if("c" in assocArr)
        printf("yes 'c'\t");
    else

        printf("no 'c'\t");
    if("d" in assocArr)
        printf("yes 'd'\n");
    else
        printf("no 'd'\n");
}