children | 易学教程

Python multiprocessing and independence of children processes

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问题 From the python terminal, I run some command like the following, to spawn a long-running child process: from multiprocessing.process import Process Process(target=LONG_RUNNING_FUNCTION).start() This command returns, and I can do other things in the python terminal, but anything printed by the child is still printed to my python terminal session. When I exit the terminal (either with exit or CTRL + D ), the exit command it hangs. If I hit CTRL + C during this hang, the child process is

js联动三级

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自己研究三级加看网上的例子得出来的 <select id="province"> <option value="">----请选择----</option> </select>省份 <select id="city"> <option value="">----请选择----</option> </select>市 <select id="country"> <option value="">----请选择----</option> </select>区 var city =[ ['合肥','宿州','淮北','阜阳','蚌埠','淮南','滁州','马鞍山','芜湖','铜陵','安庆','黄山','六安','池州','宣城','亳州'], ['广州','深圳','清远','韶关','河源','梅州','潮州','汕头','揭阳','汕尾','惠州','东莞','珠海','中山','江门','佛山','肇庆','云浮','阳江','茂名','湛江']]; var country =[[['合肥1','合肥2'],['宿州1','宿州2'],['淮北1','淮北2'],['阜阳1','阜阳2'],['蚌埠1','蚌埠2'],['淮南1','淮南2'] ,['滁州1','滁州2'],['马鞍山1','马鞍山2'],['芜湖1','芜湖2'],['铜陵1','铜陵2'],['安庆',

WPF Canvas, how to add children dynamically with MVVM code behind

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问题 Requirement: To draw one Bitmap Image (of 1024 x 1024 pixels) and rectangle(s) based on the collection of points. The rectangle should exactly fit on the pixels location over the image. There is also some text need to be added inside the rectangle. The Image will be always only one and the rectangles will be dynamically added. Current Solution: Have a canvas with Image Control. Add the the dynamic code under the code behind file ViewImageResult.xaml.cs. private void DrawResult(int left, int

PHP Simple XML remove all Children

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问题 i want to remove all children from my xml file before i fill it up again (or create an update but that seemed alot harder). So what i did is $file = "data.xml"; $xml=simplexml_load_file($file); $teller=0; foreach( $entries as $entry ) { foreach ($xml->xpath('//concerts') as $desc) { if($teller == 0) { $lol=$desc->children(); unset($lol); } $concert = $desc->addChild( 'concert' ); $concert->addChild( 'artist', array_shift( $entry ) ); $concert->addChild( 'location', array_shift( $entry ) );

WPF UserControl with multiple Children

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问题 I have a UserControl that I would like to be able to have more than one child. It already has StackPanel as it's child, so what am I doing wrong? Ultimately, I'd like for the control to include some of its own children automatically and then, when it's used, allow placing more children inside one of its elements. I tried MSDN's How to Override the Logical Tree without success. Thanks in advance. LayerPanelItem.xaml: <UserControl x:Class="Controls.LayerPanelItem" xmlns="http://schemas

get all children names from object

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问题 How can I get all names from this object? var familyTree = {name: 'Alex', children:[ {name: 'Ricky', children:'[...]'} {name: 'John', children:[{name: 'Tom', children: '[...]'}]}]}; That it would execute Alex Ricky John Tom. 回答1: You could write a simple recursive function that will traverse the contents of your tree: var familyTree = { name: 'Alex', children: [ { name: 'Ricky', children: [ ] }, { name: 'John', children: [ { name: 'Tom', children: [ ] } ] } ] }; var traverse = function(tree)

CakePHP - Relationship Question - Posts.Child belongsTo User, How to define?

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问题 Below is a posts model, and as you can see I have a belongsTo relationship on each post, so that the user details are also retrieved with the post. I would also like the exact same behaviour for the Posts.Children (see the hasMany definition below). QUESTION: How do I also apply the belongsTo relationship to the Posts.Children ( Posts.Child belongsTo User )?? <?php class Post extends AppModel { var $name = 'Post'; var $belongsTo = array( 'User' => array( 'className' => 'User', 'foreignKey' =>

jQuery: counting visible elements - efficiency/speed problems

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问题 I have some code that works fine but it's become too slow: HTML: I have a container that contains about 50 ul elements. Each ul element has a h4 heading followed by a series of li elements. The function hides the heading if no line elements are visible. Javascript/jQuery: function show_or_hide_headings() { $('#container').children('ul').each(function (i) { var $this = $(this), $h4 = $this.children(':first'); if ($this.children('li:visible').length) { $h4.show(); } else { $h4.hide(); } }); }

How can you get the parent of a UIElement?

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问题 Ok, I know that FrameworkElement , which is a direct subclass of UIElement , has a Parent property, but Panels have children of type UIElement , not FrameworkElement (Children is of type UIElementCollection ) which seems it would mean you can add UIElement s directly to a Panel. That said, if you have a UIElement and want to see if it has a parent that's a panel, the only way I know how to test this is with the VisualTreeHelper , but that's the visual tree, not the logical tree. (At least we

Should I create child textviews statically or dynamically?

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问题 I have a listview where the items contain different amount of child textviews. min 5 max 20 i've tried both ways and I only have the vm to test my apps on so I can't really tell any difference performance wise. but what's the best way to do this? should I create the 20 textviews in my xml and just hide the ones I don't use? or just create and add new textviews everytime, resulting in no "Ghost views" 回答1: Issues to realise: Code cleanliness- > Doing anything more than basic layouts in code