for-loop

问题 What is the difference when we declare variable before using in loop and when define variable in loop. I am talking about this situation int i; for(i=0; i<100; i++); and for(int i=0; i<100; i++); 回答1: In the first case it is supposed that variable i will be used also after the loop as for example int i; for(i=0; i<100; i++); printf( "i = %d\n", i ); Nevertheless it would be much better to write the following way int i = 0; for( ; i<100; i++); printf( "i = %d\n", i ); In this case we will get

问题 I keep getting this error in my For loop: Error in FUN(X[[i]], ...) : no loop for break/next, jumping to top level autoAnal <- function(x){ if(!is.numeric(x)){ next } m <- median(x, na.rm = T) a <- mean(x, na.rm = T) s <- sd(x, na.rm = T) q <- quantile(x, na.rm = T) q3 <- q[4] q1 <- q[2] outhigh <- (1.5 * q3) + IQR(x, na.rm = T) outlow <- (1.5 * q1) - IQR(x, na.rm = T) data.table(Median = m, Average = a, StDev = s, Outhigh = outhigh, Outlow = outlow) } Channel Data Channel june july december

问题 I keep getting this error in my For loop: Error in FUN(X[[i]], ...) : no loop for break/next, jumping to top level autoAnal <- function(x){ if(!is.numeric(x)){ next } m <- median(x, na.rm = T) a <- mean(x, na.rm = T) s <- sd(x, na.rm = T) q <- quantile(x, na.rm = T) q3 <- q[4] q1 <- q[2] outhigh <- (1.5 * q3) + IQR(x, na.rm = T) outlow <- (1.5 * q1) - IQR(x, na.rm = T) data.table(Median = m, Average = a, StDev = s, Outhigh = outhigh, Outlow = outlow) } Channel Data Channel june july december

问题 I have a list of URLs in a .txt file that I would like to run using selenium. Lets say that the file name is b.txt in it contains 2 urls (precisely formatted as below): https://www.google.com/,https://www.bing.com/, What I am trying to do is to make selenium run both urls (from the .txt file), however it seems that every time the code reaches the "driver.get" line, the code fails. url = open ('b.txt','r') url_rpt = url.read().split(",") options = Options() options.add_argument('--headless')

问题 Im working with a loop that creates many tables etc. and exports it into word documents with ReporteRs package. So for example I then have a word document with many pages of different graphs, tables and text. I want to insert an image (or pdf - either is fine) into it through the loop (since the loop produces many different word documents). I have downloaded the ImageMagick and magick packages to work with the images. Now I have my image in R, but I cant figure out how to add it to my

问题 This question already has answers here : Why does std::getline() skip input after a formatted extraction? (3 answers) Closed 4 years ago . I have a little problem. I've created a program that asks user to enter part's name and part's price for four diffrent parts. Each name and price fills a structure, and I have an array of four structures. When i do a for loop to fill all the names and prices, my getline functon doesn't work properly, it simply just skipps the entering part after I enter

问题 I have this function bool nameExists(players, player) { players.forEach((f) { if (f.data['name'].toLowerCase() == player.toLowerCase()) { return true; } }); return false; } It always return false, even if the condition is satisfied. Any ideas? 回答1: There is no way to return a value from forEach . Just use a for loop instead. bool nameExists(players, player) { for(var f in players) { if (f.data['name'].toLowerCase() == player.toLowerCase()) { return true; } } return false; } 回答2: For this

问题 I have this function bool nameExists(players, player) { players.forEach((f) { if (f.data['name'].toLowerCase() == player.toLowerCase()) { return true; } }); return false; } It always return false, even if the condition is satisfied. Any ideas? 回答1: There is no way to return a value from forEach . Just use a for loop instead. bool nameExists(players, player) { for(var f in players) { if (f.data['name'].toLowerCase() == player.toLowerCase()) { return true; } } return false; } 回答2: For this

问题 In a df as below: id timestamp temperature 27581 27822 2020-01-02 07:53:05.173 19.5 27582 27823 2020-01-02 07:53:05.273 20.0 27647 27888 2020-01-02 10:01:46.380 20.5 27648 27889 2020-01-02 10:01:46.480 21.0 27649 27890 2020-01-02 10:01:48.463 21.5 27650 27891 2020-01-02 10:01:48.563 22.0 27711 27952 2020-01-02 10:32:19.897 21.5 27712 27953 2020-01-02 10:32:19.997 21.0 27861 28102 2020-01-02 11:34:41.940 21.5 ... In a for-loop that generate plot, I want to print the weekday of date inside the

问题 I have a VBA macro pulling stock data every 5 minutes on the entire NYSE. This pulls everything from current price, to earnings dates, to p/e, among other metrics. I'm now trying to set up a cronjob to run a little python code to clean up the csv data before I import it into the mySQL database. Before I can set up the cronjob, I need to get the python code working... Baby steps :). I went away from python a few years ago, but am trying to use it again here. After some research, it's been