shuffle

问题 I'm getting confused about spill to disk and shuffle write . Using the default Sort shuffle manager, we use an appendOnlyMap for aggregating and combine partition records, right? Then when execution memory fill up, we start sorting map, spilling it to disk and then clean up the map for the next spill(if occur), my questions are : What is the difference between spill to disk and shuffle write? They consist basically in creating file on local file system and also record. Admit are different, so

问题 I've looked everywhere on how to shuffle/randomize a string list in C# for the windows phone 7. I'm still a beginner you could say so this is probably way out of my league, but I'm writing a simple app, and this is the base of it. I have a list of strings that I need to shuffle and output to a text block. I have bits and pieces of codes I've looked up, but I know I have it wrong. Any suggestions? 回答1: The Fisher-Yates-Durstenfeld shuffle is a proven technique that's easy to implement. Here's

问题 I'm trying to shuffle only elements of a list on 3rd till last position so the 1st two will always stay in place e.g. list = ['a?','b','c','d','e'] into list = ['a?','b','d','e','c'] and for some reason this doesn't work: list = ['a?','b','c','d','e'] import random random.shuffle(list[2:]) print list Any know what am I doing wrong?? The only thing that works for me is so far this (EDITED): lists = [['a?','b','c','d','e'],['1?','2','3','4','5','6','7']] import random for list in lists: copy =

问题 I have 5-partitions-RDD and 5 workers/executors. How can I ask Spark to save each RDD's partition on the different worker (IP)? Am I right if I say Spark can save few partitions on one worker, and 0 partitions on other workers? Means, I can specify the number of partitions, but Spark still can cache everything on a single node. Replication is not an option since RDD is huge. Workarounds I have found getPreferredLocations RDD's getPreferredLocations method does not provide a 100% warranty that

问题 What I need done is: Original State: <div class="shuffledv"> <div id="1"></div> <div id="2"></div> <div id="3"></div> </div> <div class="shuffledv"> <div id="4"></div> <div id="5"></div> <div id="6"></div> </div> After Shuffle: <div class="shuffledv"> <div id="2"></div> <div id="3"></div> <div id="1"></div> </div> <div class="shuffledv"> <div id="5"></div> <div id="4"></div> <div id="6"></div> </div> The Divs within the first div stay there but get shuffled, and the same happens for the

问题 What I need done is: Original State: <div class="shuffledv"> <div id="1"></div> <div id="2"></div> <div id="3"></div> </div> <div class="shuffledv"> <div id="4"></div> <div id="5"></div> <div id="6"></div> </div> After Shuffle: <div class="shuffledv"> <div id="2"></div> <div id="3"></div> <div id="1"></div> </div> <div class="shuffledv"> <div id="5"></div> <div id="4"></div> <div id="6"></div> </div> The Divs within the first div stay there but get shuffled, and the same happens for the

问题 I read this post about card shuffling and in many shuffling and sorting algorithms you need to swap two items in a list or array. But what does a good and efficient Swap method look like? Let's say for a T[] and for a List<T> . How would you best implement a method that swaps two items in those two? Swap(ref cards[i], ref cards[n]); // How is Swap implemented? 回答1: Well, the code you have posted ( ref cards[n] ) can only work with an array (not a list) - but you would use simply (where foo

问题 I would like to randomly reorganize the order of the numbers in a vector, in a simple one-line command? My particular vector V has 150 entries for each value from 1 to 10: V <- rep(1:10, each=150) 回答1: Yes. sample(V) From ?sample : For ‘sample’ the default for ‘size’ is the number of items inferred from the first argument, so that ‘sample(x)’ generates a random permutation of the elements of ‘x’ (or ‘1:x’). 回答2: Use sample function V<-rep(1:10, each=150) set.seed(001) # just to make it

问题 Is there some function, similar to srand() , that I need to call to make sure that std::random_shuffle() always produces different results? i.e. if I call it several times with the same data, I want the order to be different every time. How can I make sure of that? 回答1: std::random_shuffle has two forms. One that takes 2 arguments (begin/end iterators), and one that takes 3 (begin/end iterator and a random generator). The first form uses std::rand() , so you would use std::srand() to seed it

问题 I can do this in PHP but am trying to work within the BASH shell. I need to take an array and then randomly shuffle the contents and dump that to somefile.txt . So given array Heresmyarray, of elements a;b;c;d;e;f; it would produce an output file, output.txt , which would contain elements f;c;b;a;e;d; The elements need to retain the semicolon delimiter. I've seen a number of bash shell array operations but nothing that seems even close to this simple concept. Thanks for any help or