foreach

问题 Premise : I've already read this question and others, but I need some clarifications. I understand that Stream.forEach method makes the difference (not only) when dealing with parallel streams, and this explains why this //1 Stream.of("one ","two ","three ","four ","five ","six ") .parallel() .forEachOrdered(item -> System.out.print(item)); prints one two three four five six But when it comes to intermediate operations, the order is not guaranteed anymore when stream is parallelized. So this

问题 I am looping through an array using foreach. In a particular situation I need to know the value of the next element before iteration comes to that(like a prediction) element. For that I am planning to use the function next(). In documentation I just noticed that next() advances the internal array pointer forward. next() behaves like current(), with one difference. It advances the internal array pointer one place forward before returning the element value. That means it returns the next array

问题 So, finally making a relatively large jump from Java 6 to Java 8, I've read up a fair amount of Java 8 Streams API. Unfortunately, almost all the examples that have been asked are almost close to what I'm trying to figure out how to do, but not close enough. What I have is final List<Function<? super Double, Double>> myList = generateList(); final double myVal = calculate(10); private double calculate(double val) { for (Function<? super Double, Double> function : this.myList) { val +=

问题 I feel dirty every time I "break" out of a for-each construct (PHP/Javascript) So something like this: // Javascript example for (object in objectList) { if (object.test == true) { //do some process on object break; } } For large objectLists I would go through the hassle building a more elegant solution. But for small lists there is no noticeable performance issue and hence "why not?" It's quick and more importantly easy to understand and follow. But it just "feels wrong". Kind of like a goto

问题 Let's say I have 2 lists in Python and I want to loop through each one in parallel - e.g. do something with element 1 for both lists, do something with element 2 for both lists... I know that I can do this by using an index: for listIndex in range(len(list1)): doSomething(list1[listIndex]) doSomething(list2[listIndex]) But is there a way to do this more intuitively, with a foreach loop? Something like for list1Value in list1, list2Value in list2 ...? I've currently run into this situation in

问题 I have populated a list in C# script and assigned its value to SSIS object variable. Then I used that object variable to execute some SQL query by looping through For each do enumerator. I tried doing this by Foreach ado enumerator but getting error X variable doesn't contain a valid data object. Can anybody provide any inputs. 回答1: Youre using a list. Not a recordset and therefore you need to enumerate over a variable. If you want to use ADO Recordset, you need to fill a datatable instead.

问题 The question is : I have View which on model of users displays id of the user and his characteristic on foreach: @model Project.User @foreach (User user in Model) { <table class="simple-little-table" cellspacing='0'> <tr> <td>Id @user.Id </td> <td>characteristic:@user.Charact</td> <td><button id="but">User Ban</button></td> </tr> </table> } On buttonClick I Render a partial view inside a Jquery modal popup: <div id="dialog1" title="Dialog Title">@Html.Partial("UserPartial")</div> $(function (

问题 I am trying to process > 10000 xts objects saved on disk each being around 0.2 GB when loaded into R. I would like to use foreach to process these in parallel. My code works for something like 100 xts objects which I pre-load in memory, export etc. but after > 100 xts objects I hit memory limits on my machine. Example of what I am trying to do: require(TTR) require(doMPI) require(foreach) test.data <- runif(n=250*10*60*24) xts.1 <- xts(test.data, order.by=as.Date(1:length(test.data))) xts.1 <

问题 I would like to do a string replacement in all items in an array. What I have is: $row['c1'] = str_replace("&", "&", $row['c1']); $row['c2'] = str_replace("&", "&", $row['c2']); $row['c3'] = str_replace("&", "&", $row['c3']); $row['c4'] = str_replace("&", "&", $row['c4']); $row['c5'] = str_replace("&", "&", $row['c5']); $row['c6'] = str_replace("&", "&", $row['c6']); $row['c7'] = str_replace("&", "&", $row['c7']); $row['c8'] = str_replace("&", "&", $row['c8']); $row['c9'] = str_replace("&", "

问题 According to comments from documentation: http://php.net/manual/en/language.generators.overview.php We can see that thanks to generators there is huge memory usage improvement (which is obvious), but there is also 2-3 times slower execution - and that is not so obvious to me. We gain memory usage improvement at the expense of time - which is not fine. So, why is php generator slower than an array? Thanks for tips. 回答1: In computer science, when doing optimizations a lot of the times you will