我正在尝试上Kotlin所以我正在关注他们自己的this tutorial。
所以他们试图创建一个给定字符串的序列，例如：
"a vect" -> [
a vect :
a vec : t
a ve : ct
...
]
根据视频，这样做的方法如下：
val seq = sequenceOf(canonicalisedInput.lastIndex + 1 downTo 0).map {
canonicalisedInput.substring(0, it) to canonicalisedInput.substring(it)
}
我得到了我所做的（好吧，它的想法）。问题是substring需要两个Int，而it（我假设它是downTo进展中某些类型的隐式迭代器）是{{ 1}}。第二次IntProgression电话也是如此。
我错过了什么？
答案 0 :(得分：4)
您发布的代码包含错误：传递单个参数的sequenceOf(...)会返回包含该项的序列，即C:\Program Files (x86)\Jenkins>java -jar jenkins.war
Running from: C:\Program Files (x86)\Jenkins\jenkins.war
webroot: $user.home/.jenkins
ao¹t 03, 2016 5:27:01 PM org.eclipse.jetty.util.log.JavaUtilLog info
INFOS: Logging initialized @606ms
ao¹t 03, 2016 5:27:01 PM winstone.Logger logInternal
INFOS: Beginning extraction from war file
ao¹t 03, 2016 5:27:01 PM org.eclipse.jetty.util.log.JavaUtilLog warn
AVERTISSEMENT: Empty contextPath
ao¹t 03, 2016 5:27:01 PM org.eclipse.jetty.util.log.JavaUtilLog info
INFOS: jetty-9.2.z-SNAPSHOT
ao¹t 03, 2016 5:27:02 PM org.eclipse.jetty.util.log.JavaUtilLog info
INFOS: NO JSP Support for /, did not find org.eclipse.jetty.jsp.JettyJspServlet
Jenkins home directory: C:\Users\Acer\.jenkins found at: $user.home/.jenkins
ao¹t 03, 2016 5:27:03 PM org.eclipse.jetty.util.log.JavaUtilLog info
INFOS: Started w.@2e3967ea{/,file:/C:/Users/Acer/.jenkins/war/,AVAILABLE}{C:\Users\Acer\.jenkins\war}
ao¹t 03, 2016 5:27:03 PM org.eclipse.jetty.util.log.JavaUtilLog warn
AVERTISSEMENT: FAILED ServerConnector@51c668e3{HTTP/1.1}{0.0.0.0:8080}: java.net.BindException: Address already in use: bind
java.net.BindException: Address already in use: bind
at sun.nio.ch.Net.bind0(Native Method)
at sun.nio.ch.Net.bind(Unknown Source)
at sun.nio.ch.Net.bind(Unknown Source)
at sun.nio.ch.ServerSocketChannelImpl.bind(Unknown Source)
at sun.nio.ch.ServerSocketAdaptor.bind(Unknown Source)
at org.eclipse.jetty.server.ServerConnector.open(ServerConnector.java:321)
at org.eclipse.jetty.server.AbstractNetworkConnector.doStart(AbstractNetworkConnector.java:80)
at org.eclipse.jetty.server.ServerConnector.doStart(ServerConnector.java:236)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
at org.eclipse.jetty.server.Server.doStart(Server.java:366)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
at winstone.Launcher.<init>(Launcher.java:152)
at winstone.Launcher.main(Launcher.java:352)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at Main._main(Main.java:246)
at Main.main(Main.java:91)
ao¹t 03, 2016 5:27:03 PM org.eclipse.jetty.util.log.JavaUtilLog warn
AVERTISSEMENT: FAILED org.eclipse.jetty.server.Server@6221a451: java.net.BindException: Address already in use: bind
java.net.BindException: Address already in use: bind
at sun.nio.ch.Net.bind0(Native Method)
at sun.nio.ch.Net.bind(Unknown Source)
at sun.nio.ch.Net.bind(Unknown Source)
at sun.nio.ch.ServerSocketChannelImpl.bind(Unknown Source)
at sun.nio.ch.ServerSocketAdaptor.bind(Unknown Source)
at org.eclipse.jetty.server.ServerConnector.open(ServerConnector.java:321)
at org.eclipse.jetty.server.AbstractNetworkConnector.doStart(AbstractNetworkConnector.java:80)
at org.eclipse.jetty.server.ServerConnector.doStart(ServerConnector.java:236)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
at org.eclipse.jetty.server.Server.doStart(Server.java:366)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
at winstone.Launcher.<init>(Launcher.java:152)
at winstone.Launcher.main(Launcher.java:352)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at Main._main(Main.java:246)
at Main.main(Main.java:91)
ao¹t 03, 2016 5:27:03 PM org.eclipse.jetty.util.log.JavaUtilLog info
INFOS: Stopped ServerConnector@51c668e3{HTTP/1.1}{0.0.0.0:8080}
ao¹t 03, 2016 5:27:03 PM hudson.WebAppMain$4 run
INFOS: Shutting down a Jenkins instance that was still starting up
java.lang.Throwable: reason
at hudson.WebAppMain$4.run(WebAppMain.java:383)
at hudson.security.ACL.impersonate(ACL.java:198)
at hudson.WebAppMain.contextDestroyed(WebAppMain.java:374)
at org.eclipse.jetty.server.handler.ContextHandler.callContextDestroyed(ContextHandler.java:808)
at org.eclipse.jetty.servlet.ServletContextHandler.callContextDestroyed(ServletContextHandler.java:457)
at org.eclipse.jetty.server.handler.ContextHandler.doStop(ContextHandler.java:842)
at org.eclipse.jetty.servlet.ServletContextHandler.doStop(ServletContextHandler.java:215)
at org.eclipse.jetty.webapp.WebAppContext.doStop(WebAppContext.java:529)
at org.eclipse.jetty.util.component.AbstractLifeCycle.stop(AbstractLifeCycle.java:89)
at org.eclipse.jetty.util.component.ContainerLifeCycle.stop(ContainerLifeCycle.java:143)
at org.eclipse.jetty.util.component.ContainerLifeCycle.doStop(ContainerLifeCycle.java:162)
at org.eclipse.jetty.server.handler.AbstractHandler.doStop(AbstractHandler.java:73)
at org.eclipse.jetty.server.Server.doStop(Server.java:456)
at org.eclipse.jetty.util.component.AbstractLifeCycle.stop(AbstractLifeCycle.java:89)
at winstone.Launcher.shutdown(Launcher.java:305)
at winstone.Launcher.<init>(Launcher.java:165)
at winstone.Launcher.main(Launcher.java:352)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at Main._main(Main.java:246)
at Main.main(Main.java:91)
ao¹t 03, 2016 5:27:03 PM org.eclipse.jetty.util.log.JavaUtilLog info
INFOS: Stopped w.@2e3967ea{/,file:/C:/Users/Acer/.jenkins/war/,UNAVAILABLE}{C:\Users\Acer\.jenkins\war}
ao¹t 03, 2016 5:27:03 PM winstone.Logger logInternal
INFOS: Winstone shutdown successfully
ao¹t 03, 2016 5:27:03 PM winstone.Logger logInternal
GRAVE: Container startup failed
java.io.IOException: Failed to start Jetty
at winstone.Launcher.<init>(Launcher.java:154)
at winstone.Launcher.main(Launcher.java:352)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at Main._main(Main.java:246)
at Main.main(Main.java:91)
Caused by: java.net.BindException: Address already in use: bind
at sun.nio.ch.Net.bind0(Native Method)
at sun.nio.ch.Net.bind(Unknown Source)
at sun.nio.ch.Net.bind(Unknown Source)
at sun.nio.ch.ServerSocketChannelImpl.bind(Unknown Source)
at sun.nio.ch.ServerSocketAdaptor.bind(Unknown Source)
at org.eclipse.jetty.server.ServerConnector.open(ServerConnector.java:321)
at org.eclipse.jetty.server.AbstractNetworkConnector.doStart(AbstractNetworkConnector.java:80)
at org.eclipse.jetty.server.ServerConnector.doStart(ServerConnector.java:236)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
at org.eclipse.jetty.server.Server.doStart(Server.java:366)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
at winstone.Launcher.<init>(Launcher.java:152)
... 7 more
ao¹t 03, 2016 5:27:03 PM hudson.util.BootFailure publish
GRAVE: Failed to initialize Jenkins
hudson.util.HudsonFailedToLoad: java.lang.InterruptedException
at hudson.WebAppMain$3.run(WebAppMain.java:244)
Caused by: java.lang.InterruptedException
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Unknown Source)
at org.jvnet.hudson.reactor.Reactor.execute(Reactor.java:267)
at jenkins.InitReactorRunner.run(InitReactorRunner.java:45)
at jenkins.model.Jenkins.executeReactor(Jenkins.java:1010)
at jenkins.model.Jenkins.<init>(Jenkins.java:878)
at hudson.model.Hudson.<init>(Hudson.java:85)
at hudson.model.Hudson.<init>(Hudson.java:81)
at hudson.WebAppMain$3.run(WebAppMain.java:227)
ao¹t 03, 2016 5:27:03 PM jenkins.model.Jenkins cleanUp
INFOS: Stopping Jenkins
ao¹t 03, 2016 5:27:03 PM jenkins.model.Jenkins$21 onAttained
INFOS: Started termination
ao¹t 03, 2016 5:27:03 PM jenkins.model.Jenkins$21 onTaskFailed
GRAVE: Failed NioChannelSelector.cleanUp
java.lang.IllegalArgumentException: Unable to inject class jenkins.slaves.NioChannelSelector
at hudson.init.TaskMethodFinder.lookUp(TaskMethodFinder.java:125)
at hudson.init.TaskMethodFinder.invoke(TaskMethodFinder.java:104)
at hudson.init.TaskMethodFinder$TaskImpl.run(TaskMethodFinder.java:175)
at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:282)
at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:210)
at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:117)
at jenkins.model.Jenkins$20.execute(Jenkins.java:3020)
at org.jvnet.hudson.reactor.Reactor$Node.runIfPossible(Reactor.java:139)
at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:128)
at jenkins.model.Jenkins$20.execute(Jenkins.java:3020)
at org.jvnet.hudson.reactor.Reactor$Node.runIfPossible(Reactor.java:139)
at org.jvnet.hudson.reactor.Reactor.execute(Reactor.java:263)
at jenkins.model.Jenkins._cleanUpRunTerminators(Jenkins.java:3017)
at jenkins.model.Jenkins.cleanUp(Jenkins.java:2939)
at hudson.WebAppMain$3.run(WebAppMain.java:248)
ao¹t 03, 2016 5:27:03 PM jenkins.model.Jenkins$21 onAttained
INFOS: Completed termination
ao¹t 03, 2016 5:27:03 PM jenkins.model.Jenkins _cleanUpDisconnectComputers
INFOS: Starting node disconnection
ao¹t 03, 2016 5:27:03 PM jenkins.model.Jenkins _cleanUpShutdownPluginManager
INFOS: Stopping plugin manager
ao¹t 03, 2016 5:27:03 PM jenkins.model.Jenkins _cleanUpPersistQueue
INFOS: Persisting build queue
ao¹t 03, 2016 5:27:04 PM jenkins.model.Jenkins cleanUp
INFOS: Jenkins stopped。要获得一系列索引（Sequence<IntProgression>），请使用asSequence()函数：
Sequence<Int>名为second的 (canonicalisedInput.lastIndex + 1 downTo 0).asSequence().map { ... }
函数是the overload that returns the substring starting from the index passed as the argument。
而substring(...)是implicit name for the innermost lambda single parameter，在您的情况下，它是it的参数，即lambda要映射的序列项。
因此，lambda中的表达式是两个子串的一对（由to infix function创建），一个从原始字符串的开头到序列中的索引，另一个 - 从该索引到字符串的结尾。
所以代码肯定应该与索引序列一起使用，这就是为什么错误很明显。
答案 1 :(得分：3)
sequenceOf(canonicalisedInput.lastIndex + 1 downTo 0) -
此表达式创建一个由单个IntProgression项组成的序列。
如果您想将IntProgression转换为Sequence<Int>，请使用asSequence扩展功能：
(canonicalisedInput.length downTo 0).asSequence()