for-loop

问题 The command forfiles is intended to enumerate a directory and apply (a) certain command(s) on each item. With the /S the same can be accomplished for a full directory tree. What happens when the content of the enumerated directory (tree) is changed by the command(s) in the body of the forfiles command? Supposed we have the directory D:\data with the following content: file1.txt file2.txt file3.txt The output of forfiles /P "D:\data" /M "*.txt" /C "cmd /C echo @file" when executed in said

问题 I tried to overload (c)begin / (c)end functions for a class so as to be able to call C++11 range-based for loop. It works in most of the cases, but I don't manage to understand and solve one : for (auto const& point : fProjectData->getPoints()){ ... } This line returns error: Error C2662: 'MyCollection<T>::begin' : cannot convert 'this' pointer from 'const MyCollection' to 'MyCollection<T> &' because fProjectData is a pointer to const. If I make it non-const, it does work. I don't understand

问题 I want to display a list of YouTube videos and let my user edit this list. I thought of doing it like this: Make a template where this will be displayed. In this template do something like <ul>{% for plugin in page %}<li>plugin</li>{% endfor %}</ul> . Make a youtube_videos placeholder and configure it to be limited to only that type of plugin. But I don't know how to make this iteration over the plugin instances in the current page in the template. I didn't see anything about this in django

问题 I want to display a list of YouTube videos and let my user edit this list. I thought of doing it like this: Make a template where this will be displayed. In this template do something like <ul>{% for plugin in page %}<li>plugin</li>{% endfor %}</ul> . Make a youtube_videos placeholder and configure it to be limited to only that type of plugin. But I don't know how to make this iteration over the plugin instances in the current page in the template. I didn't see anything about this in django

问题 The forfiles command establishes several variables, indicated by a leading @ , which return data concerning the currently iterated item to the loop body. All the variables related to the path and name of the iterated item return the value enclosed in "" . Those are: @file , @fname , @ext , @path and @relpath . So: how can you get rid of the enclosing double-quotes? For example, the following code returns relative paths to text files in the given root directory: forfiles /P "C:\root" /M "*.txt

问题 I have a dataframe df structure(list(ID = structure(c(8L, 8L, 8L, 8L, 8L, 8L, 8L, 9L, 9L, 9L, 10L, 10L, 10L, 10L, 11L, 11L, 11L, 11L, 11L, 12L, 12L, 13L, 13L, 13L, 14L, 14L, 14L, 14L, 14L, 15L, 15L, 15L, 15L, 16L, 16L, 16L, 16L, 16L, 16L, 16L, 16L, 16L, 17L, 17L, 17L, 17L, 17L, 17L, 17L, 18L, 18L, 18L, 18L, 18L, 18L, 20L, 20L, 20L, 40L, 40L, 40L, 40L, 40L, 40L, 40L, 57L, 57L, 62L, 62L, 62L, 70L, 70L, 70L, 70L, 70L, 2L, 2L, 2L, 43L, 43L, 43L, 43L, 43L, 43L, 43L, 46L, 46L, 46L, 46L, 60L, 60L,

问题 I am having an issue on my problem where the console is saying SyntaxError: Unexpected token { and I'm not sure where it's coming from. I am a JS newbie, just learning this stuff. Would you mind pointing out where I am going wrong with my brackets please. var myArray = [4, 6, 23, 10, 1, 3]; var arrayAdditon = function (arr) { var largestNumber = arr[0]; var sumTotal; for (var i = 0; i < arr.length; i += 1) { if (arr[i] > largestNumber) { largestNumber = arr[i]; } } for (var i = 0; i < arr

问题 For loop with multiple variables in python 2.7. Hello, I am not certain how to go about this, I have a function that goes to a site and downloads a .csv file. It saves the .csv file in a particular format: name_uniqueID_dataType.csv. here is the code import requests name = "name1" id = "id1" dataType = "type1" def downloadData(): URL = "http://www.website.com/data/%s" %name #downloads the file from the website. The last part of the URL is the name r = requests.get(URL) with open("data/%s_%s_

问题 I am trying to vectorize my code and need some help. Here is a dummy example. a <- c(0, 0, 0) b <- c(0, 0, 0) c <- c(0, 0, 0) rm <- c(1, 2, 3) var1 <- c(100, 101, 102) var2 <- c(200, 201, 202) var3 <- c(300, 301, 302) mat <- data.matrix(cbind(a, b, c, rm, var1, var2, var3)) num <- 3 for (i in 1:num) { for (j in 1:num) { mat[i, j] <- mat[i, 1+num+ mat[j, "rm"]] } } 来源： https://stackoverflow.com/questions/52594597/how-to-vectorize-nested-for-loops-when-column-j-is-used-as-a-row-number-e-g-my

问题 So using the Matching Package (Link to package here) We can work through a modified GenMatch example. library(Matching) data(lalonde) #introduce an id vaiable lalonde$ID <- 1:length(lalonde$age) X = cbind(lalonde$age, lalonde$educ, lalonde$black, lalonde$hisp, lalonde$married, lalonde$nodegr, lalonde$u74, lalonde$u75, lalonde$re75, lalonde$re74) BalanceMat <- cbind(lalonde$age, lalonde$educ, lalonde$black, lalonde$hisp, lalonde$married, lalonde$nodegr, lalonde$u74, lalonde$u75, lalonde$re75,