method

find

v1_8_6_287 - Show latest stable - 4 notes - Class: Enumerable

find(...) public

Passes each entry in enum to block. Returns the first for which block is not false. If no object matches, calls ifnone and returns its result when it is specified, or returns nil

   (1..10).detect  {|i| i % 5 == 0 and i % 7 == 0 }   #=> nil
   (1..100).detect {|i| i % 5 == 0 and i % 7 == 0 }   #=> 35

Show source

/*
 *  call-seq:
 *     enum.detect(ifnone = nil) {| obj | block }  => obj or nil
 *     enum.find(ifnone = nil)   {| obj | block }  => obj or nil
 *  
 *  Passes each entry in <i>enum</i> to <em>block</em>. Returns the
 *  first for which <em>block</em> is not <code>false</code>.  If no
 *  object matches, calls <i>ifnone</i> and returns its result when it
 *  is specified, or returns <code>nil</code>
 *     
 *     (1..10).detect  {|i| i % 5 == 0 and i % 7 == 0 }   #=> nil
 *     (1..100).detect {|i| i % 5 == 0 and i % 7 == 0 }   #=> 35
 *     
 */

static VALUE
enum_find(argc, argv, obj)
    int argc;
    VALUE* argv;
    VALUE obj;
{
    VALUE memo = Qundef;
    VALUE if_none;

    rb_scan_args(argc, argv, "01", &if_none);
    rb_iterate(rb_each, obj, find_i, (VALUE)&memo);
    if (memo != Qundef) {
        return memo;
    }
    if (!NIL_P(if_none)) {
        return rb_funcall(if_none, rb_intern("call"), 0, 0);
    }
    return Qnil;
}

April 1, 2009

1 thank

Returns the element, not block result

Enumerable#find will always return the element that is found, not the result of the block provided.

March 11, 2012

0 thanks

Video Explanation of find and find_all

http://www.youtube.com/watch?v=2tTMAPT7rcw

February 12, 2015

0 thanks

Example is a Bug!

Why is the example showing the use of the #detect method and not #find? Boggles the mind!

November 17, 2015

0 thanks

@rubynooby: #find and #detect are aliases of the same underlying method. You can use them interchangeably to provide additional readability to your code (find an element to use it or detect if an element is present to do something).

http://ruby-doc.org/core-2.2.3/Enumerable.html#method-i-find

find

Related methods

Returns the element, not block result

Video Explanation of find and find_all

Example is a Bug!

Find and Detech are the same