问题描述

编写PowerShell脚本，以多维（3维）数组中第二维度的值进行过滤，并打印出结果

#三维数组源数据“A”, “11”, “Cheng Du”“B”, “21”, “Chong Qing”“C”, “31”, “Shang Hai”“D”, “41”, “Bei Jing”“E”, “51”, “Nan Jing”#从地址中过滤以Chong开头的地区, 结果需要为B, 21, Chong Qing

PowerShell脚本为：

$CityList = [System.Collections.ArrayList]::new()$CityList.Add(@(“A”,“11”,“Cheng Du”)) | Out-Null$CityList.Add(@(“B”,“21”,“Chong Qing”)) | Out-Null$CityList.Add(@(“C”,“31”,“Shang Hai”)) | Out-Null$CityList.Add(@(“D”,“41”,“Bei Jing”)) | Out-Null$CityList.Add(@(“E”,“51”,“Nan Jing”)) | Out-NullWrite-Host \"==== 开始过滤 Chong  ==== \" -ForegroundColor DarkYellow$FinalCityList = $CityList | Where-object -filterScript {$_[2] -like \"Chong*\"}Write-Host \"Final City List 类型\" -ForegroundColor Green$FinalCityList.GetType()Write-Host \"Final City 数量为: \" $FinalCityList.Count -ForegroundColor GreenWrite-Host \"\"Write-Host \"==== 循环打印List中所有元素结果 ==== \"  -ForegroundColor DarkYellowforeach( $aaa in $FinalCityList){Write-Host $aaa[0]\',\'$aaa[1]\',\'$aaa[2]}Write-Host \"\"Write-Host \"==== 直接输出对象的结果 ==== \" -ForegroundColor red$FinalCityList

输出结果 ：当过滤结果大于1时，显示正常，当过滤结果为1时，结果显示异常。结果变成了一个一位数组，Count结果为3。

这是为什么呢？

问题分析

从 $FinalCityList 的打印结果分析，当 Where-Object 查看到结果只有一个的时候，就把结果对象进行了多维到一维的转换。所以结果变为了一个包含三行内容的一位数组。

问题解决

$FinalCityList = @($CityList | Where-object -filterScript {$_[2] -like \"Chong*\"})

把 Where-Object 方法用 @() 进行对象转换即可。

完整的PowerShell脚本为：

$CityList = [System.Collections.ArrayList]::new()$CityList.Add(@(“A”,“11”,“Cheng Du”)) | Out-Null$CityList.Add(@(“B”,“21”,“Chong Qing”)) | Out-Null$CityList.Add(@(“C”,“31”,“Shang Hai”)) | Out-Null$CityList.Add(@(“D”,“41”,“Bei Jing”)) | Out-Null$CityList.Add(@(“E”,“51”,“Nan Jing”)) | Out-Nullforeach( $ccc in $CityList){Write-Host $ccc[0]\',\'$ccc[1]\',\'$ccc[2]}Write-Host \"==== 开始过滤 CityList 中包含 Chong 的城市  ==== \" -ForegroundColor Yellow$FinalCityList = @($CityList | Where-object -filterScript {$_[2] -like \"Chong*\"})Write-Host \"Final City List 类型\" -ForegroundColor Green$FinalCityList.GetType()Write-Host \"Final City 数量为: \" $FinalCityList.Count -ForegroundColor GreenWrite-Host \"\"Write-Host \"==== 循环打印List中所有元素结果 ==== \"  -ForegroundColor DarkYellowforeach( $aaa in $FinalCityList){Write-Host $aaa[0]\',\'$aaa[1]\',\'$aaa[2]}Write-Host \"\"Write-Host \"==== 直接输出对象的结果 ==== \" -ForegroundColor red$FinalCityList

参考文档

数组子表达式运算符:https://docs.microsoft.com/zh-cn/powershell/module/microsoft.powershell.core/about/about_arrays?view=powershell-7.2#the-array-sub-expression-operator

What does the \”@\” symbol do in PowerShell?：https://stackoverflow.com/questions/363884/what-does-the-symbol-do-in-powershell