假设我有一个数据集df，如下所示
col1 col2
1 A
1 B
1 C
2 B
2 B
2 C
我想要使用col1进入数据集，并使用以下代码将col2作为数组
var df2=df.groupBy("col1").agg(collect_set("col2").alias("col2"))
那么df2将是
COl1 Col2
1 A,B,C
2 B,C
如何更改代码以便拥有
COl1 Col2
1 A,B,C
2 B,B,C
答案 0 :(得分：2)
您可以执行java.lang.LinkageError: loader constraint violation: when resolving method "org.slf4j.impl.StaticLoggerBinder.getLoggerFactory()Lorg/slf4j/ILoggerFactory;" the class loader (instance of org/eclipse/osgi/internal/baseadaptor/DefaultClassLoader) of the current class, org/slf4j/LoggerFactory, and the class loader (instance of org/eclipse/osgi/internal/baseadaptor/DefaultClassLoader) for the method's defining class, org/slf4j/impl/StaticLoggerBinder, have different Class objects for the type org/slf4j/ILoggerFactory used in the signature
at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:429)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:365)
at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:155)
at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:132)
at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:273)
at org.apache.commons.beanutils.ConvertUtilsBean.<init>(ConvertUtilsBean.java:154)
at org.apache.commons.beanutils.BeanUtilsBean.<init>(BeanUtilsBean.java:113)
at org.apache.activemq.artemis.utils.uri.BeanSupport.<clinit>(BeanSupport.java:35)
at org.apache.activemq.artemis.uri.schema.serverLocator.AbstractServerLocatorSchema.newConnectionOptions(AbstractServerLocatorSchema.java:29)
at org.apache.activemq.artemis.uri.schema.serverLocator.TCPServerLocatorSchema.internalNewObject(TCPServerLocatorSchema.java:42)
at org.apache.activemq.artemis.uri.schema.serverLocator.TCPServerLocatorSchema.internalNewObject(TCPServerLocatorSchema.java:33)
at org.apache.activemq.artemis.utils.uri.URISchema.newObject(URISchema.java:86)
at org.apache.activemq.artemis.utils.uri.URISchema.newObject(URISchema.java:30)
at org.apache.activemq.artemis.utils.uri.URIFactory.newObject(URIFactory.java:59)
at org.apache.activemq.artemis.core.client.impl.ServerLocatorImpl.newLocator(ServerLocatorImpl.java:411)
at org.apache.activemq.artemis.jms.client.ActiveMQConnectionFactory.<init>(ActiveMQConnectionFactory.java:209)
at org.apache.activemq.artemis.jms.client.ActiveMQConnectionFactory.<init>(ActiveMQConnectionFactory.java:202)
at org.apache.activemq.artemis.jms.client.ActiveMQJMSConnectionFactory.<init>(ActiveMQJMSConnectionFactory.java:34)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at org.jboss.marshalling.reflect.SerializableClass.invokeConstructor(SerializableClass.java:502)
at org.jboss.marshalling.reflect.SerializableClass.callNoArgConstructor(SerializableClass.java:456)
at org.jboss.marshalling.river.RiverUnmarshaller.doReadNewObject(RiverUnmarshaller.java:1414)
at org.jboss.marshalling.river.RiverUnmarshaller.doReadObject(RiverUnmarshaller.java:275)
at org.jboss.marshalling.river.RiverUnmarshaller.doReadObject(RiverUnmarshaller.java:208)
at org.jboss.marshalling.AbstractObjectInput.readObject(AbstractObjectInput.java:41)
at org.wildfly.naming.client.remote.RemoteClientTransport.lookup(RemoteClientTransport.java:243)
at org.wildfly.naming.client.remote.RemoteContext.lambda$lookupNative$0(RemoteContext.java:190)
at org.wildfly.naming.client.NamingProvider.performExceptionAction(NamingProvider.java:222)
at org.wildfly.naming.client.remote.RemoteContext.performWithRetry(RemoteContext.java:100)
at org.wildfly.naming.client.remote.RemoteContext.lookupNative(RemoteContext.java:188)
at org.wildfly.naming.client.AbstractFederatingContext.lookup(AbstractFederatingContext.java:74)
at org.wildfly.naming.client.store.RelativeFederatingContext.lookupNative(RelativeFederatingContext.java:58)
at org.wildfly.naming.client.AbstractFederatingContext.lookup(AbstractFederatingContext.java:74)
at org.wildfly.naming.client.AbstractFederatingContext.lookup(AbstractFederatingContext.java:60)
at org.wildfly.naming.client.AbstractFederatingContext.lookup(AbstractFederatingContext.java:66)
at org.wildfly.naming.client.WildFlyRootContext.lookup(WildFlyRootContext.java:144)
at javax.naming.InitialContext.lookup(InitialContext.java:417)
at org.apache.axis2.transport.jms.JMSUtils.lookup(JMSUtils.java:687)
at org.apache.axis2.transport.jms.JMSConnectionFactory.initJMSConnectionFactory(JMSConnectionFactory.java:138)
at org.apache.axis2.transport.jms.JMSConnectionFactory.<init>(JMSConnectionFactory.java:115)
at org.apache.axis2.transport.jms.JMSConnectionFactoryManager.loadConnectionFactoryDefinitions(JMSConnectionFactoryManager.java:61)
at org.apache.axis2.transport.jms.JMSConnectionFactoryManager.<init>(JMSConnectionFactoryManager.java:48)
at org.apache.axis2.transport.jms.JMSListener.doInit(JMSListener.java:70)
at org.apache.axis2.transport.base.AbstractTransportListenerEx.init(AbstractTransportListenerEx.java:62)
at org.apache.axis2.engine.ListenerManager.init(ListenerManager.java:84)
at org.wso2.carbon.core.init.CarbonServerManager.initializeCarbon(CarbonServerManager.java:411)
at org.wso2.carbon.core.init.CarbonServerManager.start(CarbonServerManager.java:219)
at org.wso2.carbon.core.internal.CarbonCoreServiceComponent.activate(CarbonCoreServiceComponent.java:94)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.eclipse.equinox.internal.ds.model.ServiceComponent.activate(ServiceComponent.java:260)
at org.eclipse.equinox.internal.ds.model.ServiceComponentProp.activate(ServiceComponentProp.java:146)
at org.eclipse.equinox.internal.ds.model.ServiceComponentProp.build(ServiceComponentProp.java:345)
at org.eclipse.equinox.internal.ds.InstanceProcess.buildComponent(InstanceProcess.java:620)
at org.eclipse.equinox.internal.ds.InstanceProcess.buildComponents(InstanceProcess.java:197)
at org.eclipse.equinox.internal.ds.Resolver.getEligible(Resolver.java:343)
at org.eclipse.equinox.internal.ds.SCRManager.serviceChanged(SCRManager.java:222)
at org.eclipse.osgi.internal.serviceregistry.FilteredServiceListener.serviceChanged(FilteredServiceListener.java:107)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.dispatchEvent(BundleContextImpl.java:861)
at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
at org.eclipse.osgi.framework.eventmgr.ListenerQueue.dispatchEventSynchronous(ListenerQueue.java:148)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistry.publishServiceEventPrivileged(ServiceRegistry.java:819)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistry.publishServiceEvent(ServiceRegistry.java:771)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistrationImpl.register(ServiceRegistrationImpl.java:130)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistry.registerService(ServiceRegistry.java:214)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.registerService(BundleContextImpl.java:433)
at org.eclipse.equinox.http.servlet.internal.Activator.registerHttpService(Activator.java:81)
at org.eclipse.equinox.http.servlet.internal.Activator.addProxyServlet(Activator.java:60)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.init(ProxyServlet.java:40)
at org.wso2.carbon.tomcat.ext.servlet.DelegationServlet.init(DelegationServlet.java:38)
at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1269)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1182)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1072)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5362)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5660)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1700)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1690)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
而不是collect_list，因为collect_set返回collect_set：
a set of objects with duplicate elements eliminate谢谢。