loops

问题 (true or false) The space for a local variable that is declared in the body of the loop is allocated whenever the loop body is executed and deallocated when the body finishes. The answer to this question is false. But why? 回答1: The statement is false because local variable space is not allocated and deallocated. It exists on the stack and is reserved when the method is entered. To see how stack space is used, write a small test program with: public static void test() { { int a = 1; long b = 2

问题 I wanted to this: for i := 0; i < len(str); i++ { dosomethingwithrune(str[i]) // takes a rune } But it turns out that str[i] has type byte ( uint8 ) rather than rune . How can I iterate over the string by runes rather than bytes? 回答1: See this example from Effective Go : for pos, char := range "日本語" { fmt.Printf("character %c starts at byte position %d\n", char, pos) } This prints : character 日 starts at byte position 0 character 本 starts at byte position 3 character 語 starts at byte position

问题 I wanted to this: for i := 0; i < len(str); i++ { dosomethingwithrune(str[i]) // takes a rune } But it turns out that str[i] has type byte ( uint8 ) rather than rune . How can I iterate over the string by runes rather than bytes? 回答1: See this example from Effective Go : for pos, char := range "日本語" { fmt.Printf("character %c starts at byte position %d\n", char, pos) } This prints : character 日 starts at byte position 0 character 本 starts at byte position 3 character 語 starts at byte position

问题 I am working on developing and optimizing a linear model using the lm() function and subsequently the step() function for optimization. I have added a variable to my dataframe by using a random generator of 0s and 1s (50% chance each). I use this variable to subset the dataframe into a training set and a validation set If a record is not assigned to the training set it is assigned to the validation set. By using these subsets I am able to estimate how good the fit of the model is (by using

问题 I have some algorithm including a while loop: while (condition) % do something and return a result array B end Let's say: -Loop 1: B1=[1 2 3 4 5....9]; -Loop 2: B2=[10 11 12....15]; -Loop 3: B3=[16 17 18 19] ; -Loop 4: B4=[20 21 22....30]; How can I create a cell A={B1,B2,B3,B4} when the loop is finished? For my real data, the while loop may be looping 100 times or more, the above is a simplification. 回答1: You can make use of the end keyword % Initialise empty cell array A = {}; while

问题 I'm my previous question, I have asked how to iterate over multiple csv files (like 100 different files of stocks symbols) and calculate their daily returns at once. I would like to know how to call max/min values for these returns for each file and print a report. Here is the creation of dictionaries as per Mr. Trenton McKinney: import pandas as pd from pathlib import Path # create the path to the files p = Path('c:/Users/<<user_name>>/Documents/stock_files') # get all the files files = p

问题 Please find below my data ( rows are disease group 0= control, 1=Ulcerative Colitis and 2=Crohns), columns are gene expression values. structure(c(5.54312e-05, 5.6112e-06, 9.74312e-05, 1.3612e-06, 1.29312e-05, 7.2512e-06, 0.0002159302, 3.6312e-06, 0.0001467552, 1.53312e-05, 0.0009132182, 1.9312e-06, 0.0074214952, 0.0006480372, 5.1312e-06, 6.1812e-06, 4.7612e-06, 0.0001199302, 0.0008845182, 0.0008506632, 0.0002366382, 7.3912e-06, 8.5112e-06, 2.63312e-05, 0.0013685242, 1.12312e-05, 0.0001775992

问题 How does a for loop inside for loop works without a curly braces? As you can see there's two for loops inside while loop first too but they require braces but in the main statement in that nested loop no braces are required? I am confused on that can anyone explain that? #include <stdio.h> #include <string.h> #include <math.h> #include <stdlib.h> int main() { int n; scanf("%d", &n); int size=2*n-1; int start=0; int end=size-1; int a[size][size]; while(n != 0) { for(int i=start; i<=end;i++){

问题 I want know if there is a elegant method for looking if a value that continually changes in a while loop can be checked and stop the while loop if the value stops change and remains the same. For example: Value = 0 while True: value changes everytime (if value still the same break) 回答1: How about this way? BTW: Fix your typo error while is not While in python. value = 0 while True: old_value, value = value, way_to_new_value if value == old_value: break 回答2: previous = None current = object()

问题 I have an android app that sends multiple data from okhttp3 but i can't find a way to log all the data sent in php..My current log only houses the last record(Show below). My best guess is that the php file data is being overwritten until the last record..How can I log all the data sent? And yes all the data is being sent out from the android app... index.php if (isset($_POST)) { file_put_contents("post.log",print_r($_POST,true)); } Sample post.log Array ( [date] => 02 Aug, 12:22 [company] =>