What is the best way to emulate a do-while loop in Bash? I could check for the condition before entering the while loop, and then continue re-checking the condition in the loop, but that’s duplicated code. Is there a cleaner way? Pseudo code of my script: while [ current_time <= $cutoff ]; do check_if_file_present #do … Read more
Many Python programmers are probably unaware that the syntax of while loops and for loops includes an optional else: clause: for val in iterable: do_something(val) else: clean_up() The body of the else clause is a good place for certain kinds of clean-up actions, and is executed on normal termination of the loop: I.e., exiting the … Read more
This question already has answers here: PHP foreach loop key value (4 answers) Closed 2 years ago. My associative array: $arr = array( 1 => “Value1”, 2 => “Value2”, 10 => “Value10” ); Using the following code, $v is filled with $arr‘s values foreach($arr as $v){ echo($v); // Value1, Value2, Value10 } How do I … Read more
So I’m trying to make this program that will ask the user for input and store the values in an array / list. Then when a blank line is entered it will tell the user how many of those values are unique. I’m building this for real life reasons and not as a problem set. … Read more
I know that there were a lot of topics like this. And I know the basics: .forEach() operates on original array and .map() on the new one. In my case: function practice (i){ return i+1; }; var a = [ -1, 0, 1, 2, 3, 4, 5 ]; var b = [ 0 ]; var … Read more
What is the best way to guard against null in a for loop in Java? This seems ugly : if (someList != null) { for (Object object : someList) { // do whatever } } Or if (someList == null) { return; // Or throw ex } for (Object object : someList) { // do … Read more
There are apparently many ways to iterate over a collection. Curious if there are any differences, or why you’d use one way over the other. First type: List<string> someList = <some way to init> foreach(string s in someList) { <process the string> } Other Way: List<string> someList = <some way to init> someList.ForEach(delegate(string s) { … Read more
I have a loop that looks something like this: for (int i = 0; i < max; i++) { String myString = …; float myNum = Float.parseFloat(myString); myFloats[i] = myNum; } This is the main content of a method whose sole purpose is to return the array of floats. I want this method to return … Read more
I try with a loop like that // ArrayList tourists for (Tourist t : tourists) { if (t != null) { t.setId(idForm); } } But it isn’t nice. Can anyone suggest me a better solution? Some useful benchmarks to make better decision: While loop, For loop and Iterator Performance Test 18 Answers 18
I have a big performance problem in R. I wrote a function that iterates over a data.frame object. It simply adds a new column to a data.frame and accumulates something. (simple operation). The data.frame has roughly 850K rows. My PC is still working (about 10h now) and I have no idea about the runtime. dayloop2 … Read more