使用 PowerShell 解析和操作 Json 文件中的日期

Question

我需要帮助解析 JSON 文件中的日期。

简而言之，我的 PowerShell 脚本将信息从 JSON 源文件提取到 CSV。我的 Json 文件有这些字段：

[
    {
     "Type":  "Some String",
     "Score": "Some String" ,
     "Dateobtained": "2021-07-03T07:15:48.493",
     "Status": "Some String", 
     "Description": "Some String" 
    },
    { 
     "Type":  "Some String",
     "Score": "Some String" ,
     "Dateobtained": "2021-06-24T07:15:48.493",
     "Status": "Some String", 
     "Description": "Some String"
    }
]

我想过滤掉旧信息。例如，今天是 7 月 6 日，我只想包含仅在今年 7 月获得的信息（Dateobtained 不应提取 7 月之前的数据）

我已经有了这个来提取其他信息：

$json = Get-Content "source.json" | ConvertFrom-Json

$json | ForEach-Object {
# Iterate through each of the tests and create object for each
    $_.Findings| ForEach-Object {
        [PSCustomObject]@{
            'Type'       = $_.Type
            'Score'     = $_.Score
            'Status' = $_.Status
            'Description' = $_.Description
            }
    }
    
} | Export-Csv -Path "out.csv" -NoTypeInformation

我不太确定如何继续解析该日期，然后将 CSV 文件中输出的内容限制为当前月份。

提前谢谢你:-)

Answer 1

给定以下数组：

PS /> $json | ft

Type        Score       Dateobtained            Status      Description
----        -----       ------------            ------      -----------
Some String Some String 2021-07-03T07:15:48.493 Some String Some String
Some String Some String 2021-06-24T07:15:48.493 Some String Some String
Some String Some String 2021-05-24T07:15:48.493 Some String Some String
Some String Some String 2021-04-24T07:15:48.493 Some String Some String

如果您只想过滤DateObtained 在当前月份之间的那些对象（对不起我的英语），您可以这样做：

$thisMonth = [datetime]::Today.Month

$json | Where-Object {

    ([datetime]$_.dateobtained).Month -eq $thisMonth
    # OR
    # ($_.dateobtained -as [datetime]).Month -eq $thisMonth

} |
Select-Object * -ExcludeProperty Dateobtained |
Export-Csv -Path "out.csv" -NoTypeInformation

这只会产生一个对象（第一个）：

Type        Score       Status      Description
----        -----       ------      -----------
Some String Some String Some String Some String

---

注意：

如果所述属性没有实际日期，则在$_.Dateobtained 上键入[datetime] 可能会引发错误。如果您不确定，请改用 $_.Dateobtained -as [datetime]：

PS /> [datetime]'notadate'
Cannot convert value "notadate" to type "System.DateTime". Error: "The string was not recognized as a valid DateTime. There is an unknown word starting at index 0."
At line:1 char:1
+ [datetime]'notadate'
+ ~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvalidCastParseTargetInvocationWithFormatProvider

PS /> 'notadate' -as [datetime] # // No errors here

PS />