如何在swift中获取键值对元组数组？

时间：2016-10-13 19:46:55

标签： ios arrays swift tuples key-pair

我有对元组数组pickerDataVisitLocation.just我想知道如何使用uniqId ex 204从我的数组返回键值对位置

var pickerDataVisitLocation:[(uniqId:Int,location:String)] = [(203,"Home"),(204,"Hospital"),(205,"Other")]
var selectedIndex = pickerDataVisitLocation[1].uniqId
pickerDataVisitLocation[selectedIndex].location //<--fatal error: Index out of range

3 个答案:

答案 0 :(得分：7)

使用Sequence的{​​{1}}方法

您可以使用first(where:)的{​​{1}}来访问基于元组元素的第一个成员（Sequence）满足布尔要求的数组的第一个元组元素。对于生成的元组元素，只需访问元组的第二个成员（first(where:)）。

uniqId

如果找不到给定id的元组元素，则上面的方法将导致结果字符串为空（由于nil合并运算符）。作为替代方案，您可以使用可选的绑定子句仅继续从location返回非var pickerDataVisitLocation: [(uniqId: Int, location: String)] = [(203, "Home"), (204, "Hospital"), (205, "Other")] // say for a given uniqId 204 let givenId = 204 let location = pickerDataVisitLocation .first{ $0.uniqId == givenId }?.location ?? "" print(location) // Hospital ：

nil

可能是另一种选择：考虑使用字典

最后，由于元组元素的第一个成员.first，提示唯一成员，其类型var pickerDataVisitLocation: [(uniqId:Int,location:String)] = [(203,"Home"),(204,"Hospital"),(205,"Other")] // say for a given uniqId 204 let givenId = 204 if let location = pickerDataVisitLocation .first(where: { $0.uniqId == givenId })?.location { print(location) // Hospital } 为uniqId，您可能需要考虑使用字典而不是一组元组。这将简化与给定唯一Int id相关联的值的访问，但是您将松开字典中“元素”（键值对）的排序，因为字典是无序集合。

Hashable

答案 1 :(得分：3)

根据给定的代码：
试试这个

var pickerDataVisitLocation:[(uniqId:Int,location:String)] = [(203,"Home"),(204,"Hospital"),(205,"Other")]
let selectedIndex = pickerDataVisitLocation[1].uniqId
var location = ""

for item in pickerDataVisitLocation {
    if item.uniqId == selectedIndex {
        location = item.location
    }
}

print(location) //Will print Hospital here

答案 2 :(得分：1)

您可以尝试下面的内容。 

    org.apache.hadoop.hdfs.server.namenode.TransferFsImage$HttpGetFailedException: Fetch of http://nn1.cluster.com:8480/getJournal?jid=ha-cluster&segmentTxId=827873&storageInfo=-63%3A1513620929%3A0%3ACID-c43f63a9-b064-4dc6-b175-378bf0db96e3 failed with status code 500
Response message:
No realm
    at org.apache.hadoop.hdfs.server.namenode.EditLogFileInputStream$URLLog$1.run(EditLogFileInputStream.java:468)
    at org.apache.hadoop.hdfs.server.namenode.EditLogFileInputStream$URLLog$1.run(EditLogFileInputStream.java:456)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:422)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1657)
    at org.apache.hadoop.security.SecurityUtil.doAsUser(SecurityUtil.java:448)
    at org.apache.hadoop.security.SecurityUtil.doAsCurrentUser(SecurityUtil.java:442)
    at org.apache.hadoop.hdfs.server.namenode.EditLogFileInputStream$URLLog.getInputStream(EditLogFileInputStream.java:455)
    at org.apache.hadoop.hdfs.server.namenode.EditLogFileInputStream.init(EditLogFileInputStream.java:141)
    at org.apache.hadoop.hdfs.server.namenode.EditLogFileInputStream.nextOpImpl(EditLogFileInputStream.java:192)
    at org.apache.hadoop.hdfs.server.namenode.EditLogFileInputStream.nextOp(EditLogFileInputStream.java:250)
    at org.apache.hadoop.hdfs.server.namenode.EditLogInputStream.readOp(EditLogInputStream.java:85)
    at org.apache.hadoop.hdfs.server.namenode.EditLogInputStream.skipUntil(EditLogInputStream.java:151)
    at org.apache.hadoop.hdfs.server.namenode.RedundantEditLogInputStream.nextOp(RedundantEditLogInputStream.java:178)
    at org.apache.hadoop.hdfs.server.namenode.EditLogInputStream.readOp(EditLogInputStream.java:85)
    at org.apache.hadoop.hdfs.server.namenode.EditLogInputStream.skipUntil(EditLogInputStream.java:151)
    at org.apache.hadoop.hdfs.server.namenode.RedundantEditLogInputStream.nextOp(RedundantEditLogInputStream.java:178)
    at org.apache.hadoop.hdfs.server.namenode.EditLogInputStream.readOp(EditLogInputStream.java:85)
    at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadEditRecords(FSEditLogLoader.java:190)
    at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadFSEdits(FSEditLogLoader.java:143)
    at org.apache.hadoop.hdfs.server.namenode.FSImage.loadEdits(FSImage.java:837)
    at org.apache.hadoop.hdfs.server.namenode.FSImage.loadEdits(FSImage.java:818)
    at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer.doTailEdits(EditLogTailer.java:232)
    at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread.doWork(EditLogTailer.java:331)
    at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread.access$200(EditLogTailer.java:284)
    at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread$1.run(EditLogTailer.java:301)
    at org.apache.hadoop.security.SecurityUtil.doAsLoginUserOrFatal(SecurityUtil.java:415)
    at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread.run(EditLogTailer.java:297)
2016-10-14 01:38:32,375 ERROR org.apache.hadoop.hdfs.server.namenode.EditLogInputStream: Got error reading edit log input stream http://nn1.cluster.com:8480/getJournal?jid=ha-cluster&segmentTxId=827873&storageInfo=-63%3A1513620929%3A0%3ACID-c43f63a9-b064-4dc6-b175-378bf0db96e3; failing over to edit log http://nn2.cluster.com:8480/getJournal?jid=ha-cluster&segmentTxId=827873&storageInfo=-63%3A1513620929%3A0%3ACID-c43f63a9-b064-4dc6-b175-378bf0db96e3
org.apache.hadoop.hdfs.server.namenode.RedundantEditLogInputStream$PrematureEOFException: got premature end-of-file at txid 827872; expected file to go up to 827874
    at org.apache.hadoop.hdfs.server.namenode.RedundantEditLogInputStream.nextOp(RedundantEditLogInputStream.java:194)
    at org.apache.hadoop.hdfs.server.namenode.EditLogInputStream.readOp(EditLogInputStream.java:85)
    at org.apache.hadoop.hdfs.server.namenode.EditLogInputStream.skipUntil(EditLogInputStream.java:151)
    at org.apache.hadoop.hdfs.server.namenode.RedundantEditLogInputStream.nextOp(RedundantEditLogInputStream.java:178)
    at org.apache.hadoop.hdfs.server.namenode.EditLogInputStream.readOp(EditLogInputStream.java:85)
    at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadEditRecords(FSEditLogLoader.java:190)
    at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadFSEdits(FSEditLogLoader.java:143)
    at org.apache.hadoop.hdfs.server.namenode.FSImage.loadEdits(FSImage.java:837)
    at org.apache.hadoop.hdfs.server.namenode.FSImage.loadEdits(FSImage.java:818)
    at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer.doTailEdits(EditLogTailer.java:232)
    at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread.doWork(EditLogTailer.java:331)
    at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread.access$200(EditLogTailer.java:284)
    at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread$1.run(EditLogTailer.java:301)
    at org.apache.hadoop.security.SecurityUtil.doAsLoginUserOrFatal(SecurityUtil.java:415)
    at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread.run(EditLogTailer.java:297)
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