456   _.first = _.head = _.take = function(array, n, guard) {
457     if (array == null) return void 0;
458     if (n == null || guard) return array[0];
459     return _.initial(array, array.length - n);
465   _.initial = function(array, n, guard) {  argument
466     return slice.call(array, 0, Math.max(0, array.length - (n == null || guard ? 1 : n)));
471   _.last = function(array, n, guard) {  argument
472     if (array == null) return void 0;
473     if (n == null || guard) return array[array.length - 1];
474     return _.rest(array, Math.max(0, array.length - n));
480   _.rest = _.tail = _.drop = function(array, n, guard) {
481     return slice.call(array, n == null || guard ? 1 : n);
485   _.compact = function(array) {  argument
486     return _.filter(array, _.identity);
510   _.flatten = function(array, shallow) {  argument
511     return flatten(array, shallow, false);
515   _.without = function(array) {  argument
516     return _.difference(array, slice.call(arguments, 1));
522   _.uniq = _.unique = function(array, isSorted, iteratee, context) {
531     for (var i = 0, length = getLength(array); i < length; i++) {
532       var value = array[i],
533           computed = iteratee ? iteratee(value, i, array) : value;
557   _.intersection = function(array) {  argument
560     for (var i = 0, length = getLength(array); i < length; i++) {
561       var item = array[i];
573   _.difference = function(array) {  argument
575     return _.filter(array, function(value){
588   _.unzip = function(array) {  argument
589     var length = array && _.max(array, getLength).length || 0;
593       result[index] = _.pluck(array, index);
615     return function(array, predicate, context) {  argument
617       var length = getLength(array);
620         if (predicate(array[index], index, array)) return index;
632   _.sortedIndex = function(array, obj, iteratee, context) {  argument
635     var low = 0, high = getLength(array);
638       if (iteratee(array[mid]) < value) low = mid + 1; else high = mid;
645     return function(array, item, idx) {  argument
646       var i = 0, length = getLength(array);
654         idx = sortedIndex(array, item);
655         return array[idx] === item ? idx : -1;
658         idx = predicateFind(slice.call(array, i, length), _.isNaN);
662         if (array[idx] === item) return idx;