nested-loops | 易学教程

How to make a IEnumerable method parallel method

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问题 Following to this post, I want parallelize this method : public IEnumerable<string> GetAllLogs(IEnumerable<IComputer> computers) { foreach (var cpt in computers) { foreach (var log in cpt.GetLogs()) { yield return log; } } } I want the method "yield returns" a log when one of the method GetLogs is finished. If I have 4 computers which returns : Computer 01 : "a", "b", "c", "d", "e" Computer 02 : "1", "2", "3", "4", "5" Computer 03 : "alpha", "beta", "gamma", "delta", "epsilon" Computer 04 :

Nested Loop Python

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问题 count = 1 for i in range(10): for j in range(0, i): print(count, end='') count = count +1 print() input() I am writing a program that should have the output that looks like this. 1 22 333 4444 55555 666666 7777777 88888888 999999999 With the above code I am pretty close, but the way my count is working it just literally counts up and up. I just need help getting it to only count to 9 but display like above. Thanks. 回答1: You're incrementing count in the inner loop which is why you keep getting

Alternatives to nested ifelse statements in R

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Suppose we have the following data. The rows represent a country and the columns ( in05:in09 ) indicate whether that country was present in a database of interest in the given year ( 2005:2009 ). id <- c("a", "b", "c", "d") in05 <- c(1, 0, 0, 1) in06 <- c(0, 0, 0, 1) in07 <- c(1, 1, 0, 1) in08 <- c(0, 1, 1, 1) in09 <- c(0, 0, 0, 1) df <- data.frame(id, in05, in06, in07, in08, in09) I want to create a variable firstyear which indicates the first year in which the country was present in the database. Right now I do the following: df$firstyear <- ifelse(df$in05==1,2005, ifelse(df$in06==1,2006,

.BAT break out of multiple nested loop, after finishing the respective list

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问题 I know breaking out of a nested loop is fairly easy, however, I'm not sure how to do it when I'm working with multiple lists of servers. Here's the scenario: Goal: Search for sessions on a server matching a specific user ID, and also kill any disconnected sessions found Problem: I have multiple lists of farms. I want to cycle through the lists until I find the users session, and then stop when that list is finished (not stop when the session is cleared, they may have multiple sessions in the

Java : Cartesian Product of a List of Lists

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I have a problem that is really kind of a general programming question, but my implementation is in Java, so I will provide my examples that way I have a class like this: public class Foo { LinkedHashMap<String, Vector<String>> dataStructure; public Foo(LinkedHashMap<String, Vector<String>> dataStructure){ this.dataStructure = dataStructure; } public String[][] allUniqueCombinations(){ //this is what I need to do } } I need to generate a nested array from my LinkedHashMap that represents every unique combination of all values in the LHM. for example, if my LHM looks like this (pseudocode, but

How to break outer loops from inner structures that respond break (loops/switch)

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How to I break an outer loop from within an nested structure that responds to the break statement in Swift? For example: while someCondition { if someOtherCondition { switch (someValue) { case 0: // do something case 1: // exit loop case 2...5: // do something else default: break } } else { someCondition = false } } The break will only get me out of the switch , and in Swift, it has to be used as empty cases are not allowed. How can I entirely exit the loop from within the switch ? nhgrif Swift allows for labeled statements . Using a labeled statement, you can specify which which control

Variable amount of nested for loops

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Edit: I'm sorry, but I forgot to mention that I'll need the values of the counter variables. So making one loop isn't a solution I'm afraid. I'm not sure if this is possible at all, but I would like to do the following. To a function, an array of numbers is passed. Each number is the upper limit of a for loop, for example, if the array is [2, 3, 5] , the following code should be executed: for(var a = 0; a < 2; a++) { for(var b = 0; b < 3; b++) { for(var c = 0; c < 5; c++) { doSomething([a, b, c]); } } } So the amount of nested for loops is equal to the length of the array. Would there be any

How to break from nested loops in Ruby?

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问题 assume the following ruby code: bank.branches do |branch| branch.employees.each do |employee| NEXT BRANCH if employee.name = "John Doe" end end NEXT BRANCH is of course pseudocode. is there a way that i can break out of a parent loop, the way one can do so in Perl, for example (by employing loop labels)? thanks in advance. 回答1: Catch and throw might be what you are looking for: bank.branches do |branch| catch :missingyear do #:missingyear acts as a label branch.employees.each do |employee|

What's a good way to structure variable nested loops?

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问题 Suppose you're working in a language with variable length arrays (e.g. with A[i] for all i in 1..A.length ) and have to write a routine that takes n ( n : 1..8 ) variable length arrays of items in a variable length array of length n , and needs to call a procedure with every possible length n array of items where the first is chosen from the first array, the second is chosen from the second array, and so forth. If you want something concrete to visualize, imagine that your routine has to take

How to nest multiple parfor loops

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parfor is a convenient way to distribute independent iterations of intensive computations among several "workers". One meaningful restriction is that parfor -loops cannot be nested, and invariably, that is the answer to similar questions like there and there . Why parallelization across loop boundaries is so desirable Consider the following piece of code where iterations take a highly variable amount of time on a machine that allows 4 workers. Both loops iterate over 6 values, clearly hard to share among 4. for row = 1:6 parfor col = 1:6 somefun(row, col); end end It seems like a good idea to