for-loop

问题 The following is a simplified version of my code: <?php for($n=1; $n<=8; $n++): ?> <p><?php echo $n; ?></p> <p><?php echo $n; ?></p> <?php endfor; ?> I want the loop to run 8 times and I want the number in the first paragraph to increment by 1 with each loop, e.g. 1, 2, 3, 4, 5, 6, 7, 8 (this is obviously simple) However, I want the number in the second paragraph to increment by 2 with each loop, e.g... 1, 3, 5, 7, 9, 11, 13, 15 I can't figure out how to make the number in the second

问题 I've read a lot "avoid for loops with numpy". So, I tried. I was using this code (simplified version). Some auxiliary data: In[1]: import numpy as np resolution = 1000 # this parameter varies tim = np.linspace(-np.pi, np.pi, resolution) prec = np.arange(1, resolution + 1) prec = 2 * prec - 1 values = np.zeros_like(tim) My first implementation was with for loop: In[2]: for i, ti in enumerate(tim): values[i] = np.sum(np.sin(prec * ti)) Then, I got rid of the explicit for cycle, and achieved

问题 I believe I need a cursor for loop to go through the street1 column from table test_data. I have a program which needs to test each row from the table. This is what I have so far: cursor c1 is street1 from test_data Begin If Instr(street1, ‘Cnr’, 1) >= 1; Then Newstreetname := Substr(street1, Instr(street1, ‘Cnr’, 1)+3); Else if Instr(street1, ‘PO Box’, 1) >= 1; Then Newstreetname:= Substr(street1, Instr(street1, ‘PO Box’, 1)); Else if REGEXP_ Instr (street1, [\d], 1) = 0; Then Newstreetname:

问题 I have a file with JSON data in it, like so: { "Results": [ {"Id": "001", "Name": "Bob", "Items": { "Cars": "1", "Books": "3", "Phones": "1"} }, {"Id": "002", "Name": "Tom", "Items": { "Cars": "1", "Books": "3", "Phones": "1"} }, {"Id": "003", "Name": "Sally", "Items": { "Cars": "1", "Books": "3", "Phones": "1"} }] } I can not figure out how to properly loop through the JSON. I would like to loop through the data and get a Name with the Cars for each member in the dataset. How can I

问题 I read on http://www.leepoint.net/notes-java/flow/loops/foreach.html. the for each equivalent to for (int i = 0; i < arr.length; i++) { type var = arr[i]; body-of-loop } is for (type var : arr) { body-of-loop } My question is how does a for each loop work for an empty list. I know for the regular for loop, the arr.length will just evaluate to 0 and the loop wont execute. What about the for each loop? 回答1: My question is how does a for each loop work for an empty list ForEach also works in the

问题 So, I have a for-loop that looks similar to this: for var i = 0; i < results.count ; i += 1 { if (results[i] < 5) { results.removeAtIndex(i) i -= 1 } } This used to work. But when I changed it to the preferred Swift 3.0 syntax: for var i in 0..<results.count { if (results[i] < 5) { results.removeAtIndex(i) i -= 1 } } I get an array IOOBE exception because it doesn't re-check the count and continues on until the original results.count . How do I fix this? It works now, but I don't want to get

问题 With ES6 generators, I see code like this: var trivialGenerator = function *(array) { var i,item; for(var i=0; i < array.length; i++){ item = array[i]; yield item; }; }; Is it possible to write something more like the code below instead? var trivialGenerator = function *(array) { array.forEach(function *(item){ yield item; }); }; I'm asking because the classic for loop is an abomination. 回答1: No, you can't use yield inside of the inner function. But in your case you don't need it. You can

问题 I'm learning JavaScript at the moment on freecodecamp and they have an example for nested for loops in one of their excercises: var arr = [[1,2], [3,4], [5,6]]; for (var i=0; i < arr.length; i++) { for (var j=0; j < arr[i].length; j++) { console.log(arr[i][j]); } } With console.log = 1 2 3 4 5 6 undefined. I understand for loops more or less, and I understand that [i] and [j] are used to access the array (I think?). I just don't understand why at the end it just prints out those numbers? I

问题 I have for loop and within that loop I have used INSERT INTO command for 75000+ values. when i am running it consumes more time. how can I improve insertion speed,... thanks in advance... rgs tharindu 回答1: If you are using SQL Server (was not specified): Rather than many individual INSERT calls, use a Bulk method such as SQLBulkCopy BULK INSERT bcp Utility 回答2: If you have a loop with 75k inserts, you're doing it wrong Based on your comments, you need something to gererate rows for you. ;WITH

问题 I have a simple example I've drawn up. I thought it was possible to combine if statements and for loops with minimal effort in Python. Given: sublists = [number1, number2, number3] for sublist in sublists: if sublist: print(sublist) I thought I could condense the for loop to: for sublist in sublists if sublist: but this results in invalid syntax. I'm not too particular on this example, I just want a method of one lining simple if statements with loops. 回答1: if you want to filter out all the