parse 运算符

计算字符串表达式并将其值分析为一个或多个计算列。 对于未成功分析的字符串,计算列将具有 null 值。 如果不需要使用分析不成功的行,则优先使用 parse-where 运算符

语法

T| parse [ kind=kind [ flags=regexFlags ]] expressionwith [ * ] stringConstantcolumnName [:columnType] [ * ] , ...

详细了解语法约定

参数

客户 类型​​ 必需 说明
T string 要分析的表格输入。
kind string 支持的类型值之一。 默认值为 simple
regexFlags string 如果 kindregex,则可以指定要使用的正则表达式标志,例如 U 表示 ungreedy,m 表示多行模式,s 表示匹配新行 \ni 表示不区分大小写。 可以在标志中找到更多标志。
expression string 计算结果为字符串的表达式。
stringConstant string 要搜索和分析的字符串常量。
columnName string 要为其赋值的列的名称(从字符串表达式中提取)。
columnType string 一个标量值,指示要将值转换为何种类型。 默认为 string

注意

  • 分析模式不仅能够以 StringConstant 开头,还能够以 ColumnName 开头。
  • 在模式中使用 * 可跳过垃圾值。 不能在 string 类型列后使用 *
  • 如果分析的表达式不是 string 类型,则会将其转换为 string 类型。
  • 如果还希望删除或重命名某些列,请使用 project

支持的类型值

文本 说明
simple 这是默认值。 stringConstant 是一个正则字符串值,匹配是严格的。 所有字符串分隔符都应出现在分析的字符串中,并且所有扩展列都必须与所需类型匹配。
regex stringConstant 可能是正则表达式,匹配是严格的。 所有字符串分隔符(对于此模式,可以是正则表达式)都应出现在分析的字符串中,并且所有扩展列都必须与所需类型匹配。
relaxed stringConstant 是一个正则字符串值,匹配是宽松的。 所有字符串分隔符都应出现在分析的字符串中,但是扩展列可以部分匹配所需的类型。 与所需类型不匹配的扩展列将获得 null 值。

正则表达式模式

在 regex 模式下,分析会将模式转换为正则表达式。 请使用正则表达式进行匹配,并使用在内部处理的带编号的已捕获组。 例如:

parse kind=regex Col with * <regex1> var1:string <regex2> var2:long

在 parse 语句中,将由分析在内部生成的正则表达式是 .*?<regex1>(.*?)<regex2>(\-\d+)

  • * 转换为 .*?

  • string 转换为 .*?

  • long 转换为 \-\d+

返回

输入表,根据提供给运算符的列的列表进行扩展。

示例

parse 运算符提供了一种简单的方法,可通过对同一 string 表达式使用多个 extract 应用程序来 extend 表。 当表中有一个 string 列,其中包含多个要分解为单独列的值时,此结果非常有用。 例如,由开发人员 trace ("printf"/"Console.WriteLine") 语句生成的列。

在下面的示例中,假定 Traces 表的 EventText 列包含 Event: NotifySliceRelease (resourceName={0}, totalSlices={1}, sliceNumber={2}, lockTime={3}, releaseTime={4}, previousLockTime={5}) 格式的字符串。 该操作将对表进行扩展,在其中添加以下六列:resourceNametotalSlicessliceNumberlockTimereleaseTimepreviousLockTime

let Traces = datatable(EventText: string)
    [
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=23, lockTime=02/17/2016 08:40:01, releaseTime=02/17/2016 08:40:01, previousLockTime=02/17/2016 08:39:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=15, lockTime=02/17/2016 08:40:00, releaseTime=02/17/2016 08:40:00, previousLockTime=02/17/2016 08:39:00)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=20, lockTime=02/17/2016 08:40:01, releaseTime=02/17/2016 08:40:01, previousLockTime=02/17/2016 08:39:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=22, lockTime=02/17/2016 08:41:01, releaseTime=02/17/2016 08:41:00, previousLockTime=02/17/2016 08:40:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=16, lockTime=02/17/2016 08:41:00, releaseTime=02/17/2016 08:41:00, previousLockTime=02/17/2016 08:40:00)"
];
Traces  
| parse EventText with * "resourceName=" resourceName ", totalSlices=" totalSlices: long * "sliceNumber=" sliceNumber: long * "lockTime=" lockTime ", releaseTime=" releaseTime: date "," * "previousLockTime=" previousLockTime: date ")" *  
| project resourceName, totalSlices, sliceNumber, lockTime, releaseTime, previousLockTime

输出

resourceName totalSlices sliceNumber lockTime releaseTime previousLockTime
PipelineScheduler 27 15 02/17/2016 08:40:00 2016-02-17 08:40:00.0000000 2016-02-17 08:39:00.0000000
PipelineScheduler 27 23 02/17/2016 08:40:01 2016-02-17 08:40:01.0000000 2016-02-17 08:39:01.0000000
PipelineScheduler 27 20 02/17/2016 08:40:01 2016-02-17 08:40:01.0000000 2016-02-17 08:39:01.0000000
PipelineScheduler 27 16 02/17/2016 08:41:00 2016-02-17 08:41:00.0000000 2016-02-17 08:40:00.0000000
PipelineScheduler 27 22 02/17/2016 08:41:01 2016-02-17 08:41:00.0000000 2016-02-17 08:40:01.0000000

正则表达式模式

let Traces = datatable(EventText: string)
    [
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=23, lockTime=02/17/2016 08:40:01, releaseTime=02/17/2016 08:40:01, previousLockTime=02/17/2016 08:39:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=15, lockTime=02/17/2016 08:40:00, releaseTime=02/17/2016 08:40:00, previousLockTime=02/17/2016 08:39:00)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=20, lockTime=02/17/2016 08:40:01, releaseTime=02/17/2016 08:40:01, previousLockTime=02/17/2016 08:39:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=22, lockTime=02/17/2016 08:41:01, releaseTime=02/17/2016 08:41:00, previousLockTime=02/17/2016 08:40:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=16, lockTime=02/17/2016 08:41:00, releaseTime=02/17/2016 08:41:00, previousLockTime=02/17/2016 08:40:00)"
];
Traces  
| parse kind = regex EventText with "(.*?)[a-zA-Z]*=" resourceName @", totalSlices=\s*\d+\s*.*?sliceNumber=" sliceNumber: long  ".*?(previous)?lockTime=" lockTime ".*?releaseTime=" releaseTime ".*?previousLockTime=" previousLockTime: date "\\)"  
| project resourceName, sliceNumber, lockTime, releaseTime, previousLockTime

输出

resourceName sliceNumber lockTime releaseTime previousLockTime
PipelineScheduler 15 02/17/2016 08:40:00, 02/17/2016 08:40:00, 2016-02-17 08:39:00.0000000
PipelineScheduler 23 02/17/2016 08:40:01, 02/17/2016 08:40:01, 2016-02-17 08:39:01.0000000
PipelineScheduler 20 02/17/2016 08:40:01, 02/17/2016 08:40:01, 2016-02-17 08:39:01.0000000
PipelineScheduler 16 02/17/2016 08:41:00, 02/17/2016 08:41:00, 2016-02-17 08:40:00.0000000
PipelineScheduler 22 02/17/2016 08:41:01, 02/17/2016 08:41:00, 2016-02-17 08:40:01.0000000

使用正则表达式标志的正则表达式模式

如果你只想获取 resourceName,请使用以下查询:

let Traces = datatable(EventText: string)
    [
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=23, lockTime=02/17/2016 08:40:01, releaseTime=02/17/2016 08:40:01, previousLockTime=02/17/2016 08:39:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=15, lockTime=02/17/2016 08:40:00, releaseTime=02/17/2016 08:40:00, previousLockTime=02/17/2016 08:39:00)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=20, lockTime=02/17/2016 08:40:01, releaseTime=02/17/2016 08:40:01, previousLockTime=02/17/2016 08:39:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=22, lockTime=02/17/2016 08:41:01, releaseTime=02/17/2016 08:41:00, previousLockTime=02/17/2016 08:40:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=16, lockTime=02/17/2016 08:41:00, releaseTime=02/17/2016 08:41:00, previousLockTime=02/17/2016 08:40:00)"
];
Traces
| parse kind = regex EventText with * "resourceName=" resourceName ',' *
| project resourceName

输出

resourceName
PipelineScheduler, totalSlices=27, sliceNumber=23, lockTime=02/17/2016 08:40:01, releaseTime=02/17/2016 08:40:01
PipelineScheduler, totalSlices=27, sliceNumber=15, lockTime=02/17/2016 08:40:00, releaseTime=02/17/2016 08:40:00
PipelineScheduler, totalSlices=27, sliceNumber=20, lockTime=02/17/2016 08:40:01, releaseTime=02/17/2016 08:40:01
PipelineScheduler, totalSlices=27, sliceNumber=22, lockTime=02/17/2016 08:41:01, releaseTime=02/17/2016 08:41:00
PipelineScheduler, totalSlices=27, sliceNumber=16, lockTime=02/17/2016 08:41:00, releaseTime=02/17/2016 08:41:00

由于默认模式为 greedy,因此不会获得预期结果。 如果有一些记录,其中的 resourceName 有时显示为小写,有时显示为大写,则对于某些值,你可能会得到 null。

若要获得想要的结果,请采用非 greedy 的 U 标志运行查询,并禁用区分大小写的 i 正则表达式标志。

let Traces = datatable(EventText: string)
    [
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=23, lockTime=02/17/2016 08:40:01, releaseTime=02/17/2016 08:40:01, previousLockTime=02/17/2016 08:39:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=15, lockTime=02/17/2016 08:40:00, releaseTime=02/17/2016 08:40:00, previousLockTime=02/17/2016 08:39:00)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=20, lockTime=02/17/2016 08:40:01, releaseTime=02/17/2016 08:40:01, previousLockTime=02/17/2016 08:39:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=22, lockTime=02/17/2016 08:41:01, releaseTime=02/17/2016 08:41:00, previousLockTime=02/17/2016 08:40:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=16, lockTime=02/17/2016 08:41:00, releaseTime=02/17/2016 08:41:00, previousLockTime=02/17/2016 08:40:00)"
];
Traces
| parse kind = regex flags = Ui EventText with * "RESOURCENAME=" resourceName ',' *
| project resourceName

输出

resourceName
PipelineScheduler
PipelineScheduler
PipelineScheduler
PipelineScheduler
PipelineScheduler

如果分析的字符串具有换行符,请使用标志 s 来分析文本。

let Traces = datatable(EventText: string)
    [
    "Event: NotifySliceRelease (resourceName=PipelineScheduler\ntotalSlices=27\nsliceNumber=23\nlockTime=02/17/2016 08:40:01\nreleaseTime=02/17/2016 08:40:01\npreviousLockTime=02/17/2016 08:39:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler\ntotalSlices=27\nsliceNumber=15\nlockTime=02/17/2016 08:40:00\nreleaseTime=02/17/2016 08:40:00\npreviousLockTime=02/17/2016 08:39:00)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler\ntotalSlices=27\nsliceNumber=20\nlockTime=02/17/2016 08:40:01\nreleaseTime=02/17/2016 08:40:01\npreviousLockTime=02/17/2016 08:39:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler\ntotalSlices=27\nsliceNumber=22\nlockTime=02/17/2016 08:41:01\nreleaseTime=02/17/2016 08:41:00\npreviousLockTime=02/17/2016 08:40:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler\ntotalSlices=27\nsliceNumber=16\nlockTime=02/17/2016 08:41:00\nreleaseTime=02/17/2016 08:41:00\npreviousLockTime=02/17/2016 08:40:00)"
];
Traces
| parse kind=regex flags=s EventText with * "resourceName=" resourceName: string "(.*?)totalSlices=" totalSlices: long "(.*?)lockTime=" lockTime: datetime "(.*?)releaseTime=" releaseTime: datetime "(.*?)previousLockTime=" previousLockTime: datetime "\\)" 
| project-away EventText

输出

resourceName totalSlices lockTime releaseTime previousLockTime
PipelineScheduler
27 2016-02-17 08:40:00.0000000 2016-02-17 08:40:00.0000000 2016-02-17 08:39:00.0000000
PipelineScheduler
27 2016-02-17 08:40:01.0000000 2016-02-17 08:40:01.0000000 2016-02-17 08:39:01.0000000
PipelineScheduler
27 2016-02-17 08:40:01.0000000 2016-02-17 08:40:01.0000000 2016-02-17 08:39:01.0000000
PipelineScheduler
27 2016-02-17 08:41:00.0000000 2016-02-17 08:41:00.0000000 2016-02-17 08:40:00.0000000
PipelineScheduler
27 2016-02-17 08:41:01.0000000 2016-02-17 08:41:00.0000000 2016-02-17 08:40:01.0000000

Relaxed 模式

在此示例中,对于 Relaxed 模式,totalSlices 扩展列必须是 long 类型。 但是,在分析的字符串中,它的值是 nonValidLongValue。 在 releaseTime 扩展列中,不能将值 nonValidDateTime 分析为 datetime。 这两个扩展列将获得 null 值,而其他扩展列(例如 sliceNumber)仍会获得正确的值。

如果将选项 kind = simple 用于下面的同一查询,则对于所有扩展列,你都会获得 null 值。 此选项在扩展列上是严格的,这是 relaxed 模式和 simple 模式之间的差异。

注意

在 relaxed 模式下,可以对扩展列进行部分匹配。

let Traces = datatable(EventText: string)
    [
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=23, lockTime=02/17/2016 08:40:01, releaseTime=nonValidDateTime 08:40:01, previousLockTime=02/17/2016 08:39:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=15, lockTime=02/17/2016 08:40:00, releaseTime=nonValidDateTime, previousLockTime=02/17/2016 08:39:00)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=nonValidLongValue, sliceNumber=20, lockTime=02/17/2016 08:40:01, releaseTime=nonValidDateTime 08:40:01, previousLockTime=02/17/2016 08:39:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=27, sliceNumber=22, lockTime=02/17/2016 08:41:01, releaseTime=02/17/2016 08:41:00, previousLockTime=02/17/2016 08:40:01)",
    "Event: NotifySliceRelease (resourceName=PipelineScheduler, totalSlices=nonValidLongValue, sliceNumber=16, lockTime=02/17/2016 08:41:00, releaseTime=02/17/2016 08:41:00, previousLockTime=02/17/2016 08:40:00)"
];
Traces
| parse kind=relaxed EventText with * "resourceName=" resourceName ", totalSlices=" totalSlices: long ", sliceNumber=" sliceNumber: long * "lockTime=" lockTime ", releaseTime=" releaseTime: date "," * "previousLockTime=" previousLockTime: date ")" *
| project-away EventText

输出

resourceName totalSlices sliceNumber lockTime releaseTime previousLockTime
PipelineScheduler 27 15 02/17/2016 08:40:00 2016-02-17 08:39:00.0000000
PipelineScheduler 27 23 02/17/2016 08:40:01 2016-02-17 08:39:01.0000000
PipelineScheduler 20 02/17/2016 08:40:01 2016-02-17 08:39:01.0000000
PipelineScheduler 16 02/17/2016 08:41:00 2016-02-17 08:41:00.0000000 2016-02-17 08:40:00.0000000
PipelineScheduler 27 22 02/17/2016 08:41:01 2016-02-17 08:41:00.0000000 2016-02-17 08:40:01.0000000