SparkSQL: apply aggregate functions to a list of c
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试):问题: Isthereawaytoapplyanaggregatefunctiontoall(oralistof)columnsofadataframe,whendoingagroupBy?Inotherwords,isthereawaytoavoiddoingthisforeverycolumn...
What does '<?=' mean in PHP?
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试):问题: <?php $a=1; ?> <?=$a;?> Whatdoes<?=meanexactly? 回答1: It\'sashorthandfor<?phpecho$a;?>. It\'senabledbydefaultsince5.4re...
Visual Studio support for new C / C++ standards?
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试):问题: IkeepreadingaboutC99andC++11andallthesetotallysweetthingsthataregettingaddedtothelanguagestandardthatmightbenicetousesomeday.However,wecurrentlyl...
Getting a sub-array from an existing array
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试):问题: IhaveanarrayXof10elements.IwouldliketocreateanewarraycontainingalltheelementsfromXthatbeginatindex3andendsinindex7.SureIcaneasilywritealoopthatwi...
Java pass by reference
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试):问题: Whatisthedifferencebetweenthis2codes: CodeA: FoomyFoo; myFoo=createfoo(); where publicFoocreateFoo() { Foofoo=newFoo(); returnfoo; } Vs.Co...