Usually, I replace a recursive algorithm by an iterative algorithm by pushing the parameters that would normally be passed to the recursive function onto a stack. In fact, you are replacing the program stack by one of your own. var stack = []; stack.push(firstObject); // while not empty while (stack.length) { // Pop off end … Read more
I use a for loop to iterate the string and use charAt() to get each character to examine it. Since the String is implemented with an array, the charAt() method is a constant time operation. String s = “…stuff…”; for (int i = 0; i < s.length(); i++){ char c = s.charAt(i); //Process char } … Read more
What they mean by non-false is: return true; So this code: var arr = [“one”, “two”, “three”, “four”, “five”]; $.each(arr, function(i) { if (arr[i] == ‘three’) { return true; } console.log(arr[i]); }); <script src=”https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js”></script> will log one, two, four, five.
The generally-preferred code for 10.5+/iOS. for (id object in array) { // do something with object } This construct is used to enumerate objects in a collection which conforms to the NSFastEnumeration protocol. This approach has a speed advantage because it stores pointers to several objects (obtained via a single method call) in a buffer … Read more
Why are there two nested iterations? For me it produces the same list of data with only one iteration: for single_date in (start_date + timedelta(n) for n in range(day_count)): print … And no list gets stored, only one generator is iterated over. Also the “if” in the generator seems to be unnecessary. After all, a … Read more
Iteration is a general term for taking each item of something, one after another. Any time you use a loop, explicit or implicit, to go over a group of items, that is iteration. In Python, iterable and iterator have specific meanings. An iterable is an object that has an __iter__ method which returns an iterator, … Read more
As Johannes pointed out, for c in “string”: #do something with c You can iterate pretty much anything in python using the for loop construct, for example, open(“file.txt”) returns a file object (and opens the file), iterating over it iterates over lines in that file with open(filename) as f: for line in f: # do … Read more
For iterating on keys of Arrays, Strings, or Objects, use for .. in : for (let key in yourobject) { console.log(key, yourobject[key]); } With ES6, if you need both keys and values simultaneously, do for (let [key, value] of Object.entries(yourobject)) { console.log(key, value); } To avoid logging inherited properties, check with hasOwnProperty : for (let … Read more
The three forms of looping are nearly identical. The enhanced for loop: for (E element : list) { . . . } is, according to the Java Language Specification, identical in effect to the explicit use of an iterator with a traditional for loop. In the third case, you can only modify the list contents … Read more
You can use a list comprehension to create a new list containing only the elements you don’t want to remove: somelist = [x for x in somelist if not determine(x)] Or, by assigning to the slice somelist[:], you can mutate the existing list to contain only the items you want: somelist[:] = [x for x … Read more