method

rehash

v1_8_7_330 - Show latest stable - 0 notes - Class: Hash

rehash() public

Rebuilds the hash based on the current hash values for each key. If values of key objects have changed since they were inserted, this method will reindex hsh. If Hash#rehash is called while an iterator is traversing the hash, an IndexError will be raised in the iterator.

a = [ "a", "b" ]
c = [ "c", "d" ]
h = { a => 100, c => 300 }
h[a]       #=> 100
a[0] = "z"
h[a]       #=> nil
h.rehash   #=> {["z", "b"]=>100, ["c", "d"]=>300}
h[a]       #=> 100

Show source

/*
 *  call-seq:
 *     hsh.rehash -> hsh
 *
 *  Rebuilds the hash based on the current hash values for each key. If
 *  values of key objects have changed since they were inserted, this
 *  method will reindex <i>hsh</i>. If <code>Hash#rehash</code> is
 *  called while an iterator is traversing the hash, an
 *  <code>IndexError</code> will be raised in the iterator.
 *
 *     a = [ "a", "b" ]
 *     c = [ "c", "d" ]
 *     h = { a => 100, c => 300 }
 *     h[a]       #=> 100
 *     a[0] = "z"
 *     h[a]       #=> nil
 *     h.rehash   #=> {["z", "b"]=>100, ["c", "d"]=>300}
 *     h[a]       #=> 100
 */

static VALUE
rb_hash_rehash(hash)
    VALUE hash;
{
    st_table *tbl;

    rb_hash_modify(hash);
    tbl = st_init_table_with_size(&objhash, RHASH(hash)->tbl->num_entries);
    rb_hash_foreach(hash, rb_hash_rehash_i, (st_data_t)tbl);
    st_free_table(RHASH(hash)->tbl);
    RHASH(hash)->tbl = tbl;

    return hash;
}

rehash

Related methods