我经常忘了正则表达式修饰符m和s与他们之间的分歧.什么是记住它们的好方法?
据我了解,他们是:
"m"是用于多线,以便
^和$将匹配字符串和字符串多次的结束的开始.(除以\n)'s'是这样的,即使是换行符,点也会匹配
通常,我只是使用
/some_pattern/ism
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但相应地使用它们可能更好(在我的情况下通常是"s").
你认为什么是记住它们的好方法,而不是忘记每次都是哪一个?
我在ionicframework网站上找不到相关信息.例如,我在react.parts网站上看到了很多来自react-native的例子,例如使用react-native我可以在谷歌地图自定义对象,形状,标记动画等上渲染,但另一方面,Ionic2呈现谷歌地图作为webview.那么,Ionic 2是原生的还是基于webview的?
当火花正在运行测试与sbt.我得到这个例外:
18:58:49.049 [sparkDriver-akka.actor.default-dispatcher-2] ERROR akka.actor.ActorSystemImpl - Uncaught fatal error from thread [sparkDriver-akka.remote.default-remote-dispatcher-5] shutting down ActorSystem [sparkDriver]
java.lang.VerifyError: (class: org/jboss/netty/channel/socket/nio/NioWorkerPool, method: createWorker signature: (Ljava/util/concurrent/Executor;)Lorg/jboss/netty/channel/socket/nio/AbstractNioWorker;) Wrong return type in function
at akka.remote.transport.netty.NettyTransport.<init>(NettyTransport.scala:283) ~[akka-remote_2.11-2.3.4-spark.jar:na]
at akka.remote.transport.netty.NettyTransport.<init>(NettyTransport.scala:240) ~[akka-remote_2.11-2.3.4-spark.jar:na]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_45]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_45]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_45]
at java.lang.reflect.Constructor.newInstance(Constructor.java:422) ~[na:1.8.0_45]
at akka.actor.ReflectiveDynamicAccess$$anonfun$createInstanceFor$2.apply(DynamicAccess.scala:78) ~[akka-actor_2.11-2.3.4-spark.jar:na]
at scala.util.Try$.apply(Try.scala:192) ~[scala-library-2.11.7.jar:0.13.8]
at akka.actor.ReflectiveDynamicAccess.createInstanceFor(DynamicAccess.scala:73) ~[akka-actor_2.11-2.3.4-spark.jar:na]
at akka.actor.ReflectiveDynamicAccess$$anonfun$createInstanceFor$3.apply(DynamicAccess.scala:84) ~[akka-actor_2.11-2.3.4-spark.jar:na]
at akka.actor.ReflectiveDynamicAccess$$anonfun$createInstanceFor$3.apply(DynamicAccess.scala:84) ~[akka-actor_2.11-2.3.4-spark.jar:na]
at scala.util.Success.flatMap(Try.scala:231) ~[scala-library-2.11.7.jar:0.13.8]
at akka.actor.ReflectiveDynamicAccess.createInstanceFor(DynamicAccess.scala:84) ~[akka-actor_2.11-2.3.4-spark.jar:na]
at akka.remote.EndpointManager$$anonfun$9.apply(Remoting.scala:692) ~[akka-remote_2.11-2.3.4-spark.jar:na]
at akka.remote.EndpointManager$$anonfun$9.apply(Remoting.scala:684) ~[akka-remote_2.11-2.3.4-spark.jar:na]
at scala.collection.TraversableLike$WithFilter$$anonfun$map$2.apply(TraversableLike.scala:728) ~[scala-library-2.11.7.jar:0.13.8]
at scala.collection.Iterator$class.foreach(Iterator.scala:742) ~[scala-library-2.11.7.jar:0.13.8] …Run Code Online (Sandbox Code Playgroud) 我有一个简单的函数在数字前添加零:
function validateString(length, str){
var newStr = '' + str;
for (var i = str.length; i < length; i++)
newStr = '0' + newStr;
return newStr;
}
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我需要更改什么(变量的类型?)以使其适用于数字?
validateString(12,2);
"2" // Unexpected rezult
validateString(12,'2');
"000000000002"
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