Using a foreach loop without a key: foreach($array as $item) { echo $item[‘filename’]; echo $item[‘filepath’]; // To know what’s in $item echo ‘<pre>’; var_dump($item); } Using a foreach loop with a key: foreach($array as $i => $item) { echo $array[$i][‘filename’]; echo $array[$i][‘filepath’]; // $array[$i] is same as $item } Using a for loop: for ($i … Read more
You can zip the list with itself sans the first element: a = [5, 7, 11, 4, 5] for previous, current in zip(a, a[1:]): print(previous, current) This works even if your list has no elements or only 1 element (in which case zip returns an empty iterable and the code in the for loop never … Read more
You’re modifying the list while you iterate over it. That means that the first time through the loop, i == 1, so 1 is removed from the list. Then the for loop goes to the second item in the list, which is not 2, but 3! Then that’s removed from the list, and then the … Read more
Cache coherence. When you scan horizontally, your data will be closer together in memory, so you will have less cache misses and thus performance will be faster. For a small enough rectangle, this won’t matter.
You can achieve desired outcome from the other end by making the prototype methods not enumerable: Object.defineProperty(Array.prototype, “containsKey”, { enumerable: false, value: function(obj) { for(var key in this) if (key == obj) return true; return false; } }); This usually works better if you have control over method definitions, and in particular if you have … Read more
The final function does not get called because async.forEach requires that you call the callback function for every element. Use something like this: async.forEach(Object.keys(dataObj), function (item, callback){ console.log(item); // print the key // tell async that that particular element of the iterator is done callback(); }, function(err) { console.log(‘iterating done’); });
but on the other hand it creates a completely useless list of integers just to loop over them. Isn’t it a waste of memory, especially as far as big numbers of iterations are concerned? That is what xrange(n) is for. It avoids creating a list of numbers, and instead just provides an iterator object. In … Read more
Postgres 9.1 added FOREACH to loop over arrays: DO $do$ DECLARE _arr int[] := ‘{1,2,3,4}’; _elem int; — matching element type BEGIN FOREACH _elem IN ARRAY _arr LOOP RAISE NOTICE ‘%’, _elem; END LOOP; END $do$; db<>fiddle here Works for multi-dimensional arrays, too: Postgres flattens the array and iterates over all elements. To loop over … Read more
same way you did the fill in, but reverse the indexes: >>> for j in range(columns): … for i in range(rows): … print mylist[i][j], … 0,0 1,0 2,0 0,1 1,1 2,1 >>>
If using goto simplifies the code, then it would be appropriate. for (;;) { for (;;) { break; /* breaks inner loop */ } for (;;) { goto outer; /* breaks outer loop */ } } outer:;