遍历 JSON 文件 PowerShell
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Iterating through a JSON file PowerShell
提问by Omen9876
I am trying to loop through the below JSON file in PowerShell.
我正在尝试在 PowerShell 中遍历以下 JSON 文件。
Without specifically naming the top tags (e.g. 17443 and 17444), as I do not know them in advance I cannot find a way to loop through the data.
没有特别命名顶部标签（例如 17443 和 17444），因为我事先不知道它们，所以我找不到循环数据的方法。
I want to output tags 3, 4 and 5 (title, firstname, surname) for all the records.
我想为所有记录输出标签 3、4 和 5（标题、名字、姓氏）。
How would I accomplish that?
我将如何做到这一点？
{
"17443":{
"sid":"17443",
"nid":"7728",
"submitted":"1436175407",
"data":{
"3":{
"value":[
"Mr"
]
},
"4":{
"value":[
"Hyman"
]
},
"5":{
"value":[
"Cawles"
]
}
} },
"17444":{
"sid":"17444",
"nid":"7728",
"submitted":"1436891400",
"data":{
"3":{
"value":[
"Miss"
]
},
"4":{
"value":[
"Charlotte"
]
},
"5":{
"value":[
"Tann"
]
}
}
},
"17445":{
"sid":"17445",
"nid":"7728",
"submitted":"1437142325",
"data":{
"3":{
"value":[
"Mr"
]
},
"4":{
"value":[
"John"
]
},
"5":{
"value":[
"Brokland"
]
}
}
}
}
I can access the data with the code below, but I want to avoid putting in 17443, 17444, etc.
我可以使用下面的代码访问数据，但我想避免输入 17443、17444 等。
$data = ConvertFrom-Json $json
foreach ($i in $data.17443)
{
foreach ($t in $i.data.3)
{
Write-Host $t.value
}
foreach ($t in $i.data.4)
{
Write-Host $t.value
}
foreach ($t in $i.data.5)
{
Write-Host $t.value
}
}
回答by Tomalak
PowerShell 3.0+
PowerShell 3.0+
In PowerShell 3.0 and higher (see: Determine installed PowerShell version) you can use the ConvertFrom-Jsoncmdlet to convert a JSON string into a PowerShell data structure.
在 PowerShell 3.0 及更高版本（请参阅：确定安装的 PowerShell 版本）中，您可以使用ConvertFrom-Jsoncmdlet 将 JSON 字符串转换为 PowerShell 数据结构。
That's convenient and unfortunate at the same time - convenient, because it's very easy to consume JSON, unfortunate because ConvertFrom-Jsongives you PSCustomObjects, and they are hard to iterate over as key-value pairs.
这既方便又不幸 - 方便，因为它很容易使用 JSON，不幸的是因为ConvertFrom-Json给了你PSCustomObjects，并且它们很难作为键值对迭代。
When you know the keys then there is nothing to iterate - you just access them directly, e.g. $result.thisKey.then.thatKey.array[1], and you're done.
当您知道密钥时，就没有什么可迭代的了——您只需直接访问它们，例如$result.thisKey.then.thatKey.array[1]，就完成了。
But in this particular JSON, the keys seem to be dynamic/not known ahead of time, like "17443"or "17444". That means we need something that can turn a PSCustomObjectinto a key-value list that foreachcan understand.
但是在这个特定的 JSON 中，键似乎是动态的/提前未知，例如"17443"或"17444"。这意味着我们需要一些可以将 aPSCustomObject转换为foreach可以理解的键值列表的东西。
# helper to turn PSCustomObject into a list of key/value pairs
function Get-ObjectMembers {
[CmdletBinding()]
Param(
[Parameter(Mandatory=$True, ValueFromPipeline=$True)]
[PSCustomObject]$obj
)
$obj | Get-Member -MemberType NoteProperty | ForEach-Object {
$key = $_.Name
[PSCustomObject]@{Key = $key; Value = $obj."$key"}
}
}
Now we can traverse the object graph and produce a list of output objects with Title, FirstNameand LastName
现在我们可以遍历对象图并生成一个输出对象列表Title，FirstName并且LastName
$json = '{"17443": {"17444": {"sid": "17444","nid": "7728","submitted": "1436891400","data": {"3": {"value": ["Miss"]},"4": {"value": ["Charlotte"]},"5": {"value": ["Tann"]}}},"17445": {"sid": "17445","nid": "7728","submitted": "1437142325","data": {"3": {"value": ["Mr"]},"4": {"value": ["John"]},"5": {"value": ["Brokland"]}}},"sid": "17443","nid": "7728","submitted": "1436175407","data": {"3": {"value": ["Mr"]},"4": {"value": ["Hyman"]},"5": {"value": ["Cawles"]}}}}'
$json | ConvertFrom-Json | Get-ObjectMembers | foreach {
$_.Value | Get-ObjectMembers | where Key -match "^\d+$" | foreach {
[PSCustomObject]@{
Title = $_.value.data."3".value | select -First 1
FirstName = $_.Value.data."4".value | select -First 1
LastName = $_.Value.data."5".value | select -First 1
}
}
}
Output
输出
Title FirstName LastName ----- --------- -------- Miss Charlotte Tann Mr John Brokland
PowerShell 2.0 / Alternative approach
PowerShell 2.0 / 替代方法
An alternative approach that also works for PowerShell 2.0 (which does not support some of the constructs above) would involve using the .NET JavaScriptSerializer classto handle the JSON:
另一种适用于 PowerShell 2.0（不支持上述某些结构）的替代方法是使用 .NET JavaScriptSerializer 类来处理 JSON：
Add-Type -AssemblyName System.Web.Extensions
$JS = New-Object System.Web.Script.Serialization.JavaScriptSerializer
Now we can do a very similar operation—even a bit simpler than above, because JavaScriptSerializer gives you regular Dictionaries, which are easy to iterate over as key-value pairs via the GetEnumerator()method:
现在我们可以做一个非常相似的操作——甚至比上面的简单一点，因为 JavaScriptSerializer 为您提供常规Dictionaries，它们很容易通过以下GetEnumerator()方法作为键值对进行迭代：
$json = '{"17443": {"17444": {"sid": "17444","nid": "7728","submitted": "1436891400","data": {"3": {"value": ["Miss"]},"4": {"value": ["Charlotte"]},"5": {"value": ["Tann"]}}},"17445": {"sid": "17445","nid": "7728","submitted": "1437142325","data": {"3": {"value": ["Mr"]},"4": {"value": ["John"]},"5": {"value": ["Brokland"]}}},"sid": "17443","nid": "7728","submitted": "1436175407","data": {"3": {"value": ["Mr"]},"4": {"value": ["Hyman"]},"5": {"value": ["Cawles"]}}}}'
$data = $JS.DeserializeObject($json)
$data.GetEnumerator() | foreach {
$_.Value.GetEnumerator() | where { $_.Key -match "^\d+$" } | foreach {
New-Object PSObject -Property @{
Title = $_.Value.data."3".value | select -First 1
FirstName = $_.Value.data."4".value | select -First 1
LastName = $_.Value.data."5".value | select -First 1
}
}
}
The output is the same:
输出是一样的：
Title FirstName LastName ----- --------- -------- Miss Charlotte Tann Mr John Brokland
If you have JSON larger than 4 MB, set the JavaScriptSerializer.MaxJsonLengthpropertyaccordingly.
如果您的 JSON 大于 4 MB，请相应地设置该JavaScriptSerializer.MaxJsonLength属性。
On reading JSON from files
从文件中读取 JSON
If you read from a file, use Get-Content -Raw -Encoding UTF-8.
如果您从文件中读取，请使用Get-Content -Raw -Encoding UTF-8.
-Rawbecause otherwiseGet-Contentreturns an array of individual lines andJavaScriptSerializer.DeserializeObjectcan't handle that. Recent Powershell versions seem to have improved type-conversion for .NET function arguments, so it might not error out on your system, but if it does (or just to be safe), use-Raw.-Encodingbecause it's wise to specify a text file's encoding when you read it andUTF-8is the most probable value for JSON files.
-Raw因为否则会Get-Content返回一组单独的行并且JavaScriptSerializer.DeserializeObject无法处理。最近的 Powershell 版本似乎改进了 .NET 函数参数的类型转换，因此它可能不会在您的系统上出错，但如果它出错（或只是为了安全），请使用-Raw.-Encoding因为在阅读时指定文本文件的编码是明智的，并且UTF-8是 JSON 文件最可能的值。
Notes
笔记
- When you build JSON that contains items with unpredictable keys, prefer an array structure like
{items: [{key: 'A', value: 0}, {key: 'B', value: 1}]}over{'A': 0, 'B': 1}. The latter seems more intuitive, but it's both harder to generate and harder to consume. ConvertFrom-Json()gives you a PowerShell custom object (PSCustomObject) that reflects the data in the JSON string.- You can loop though the properties of a custom object with
Get-Member -type NoteProperty - You can access the properties of an object dynamically using the
$object."$propName"syntax, alternatively$object."$(some PS expression)". - You can create your own custom object and initialize it with a bunch of properties with
New-Object PSObject -Property @{...}, alternatively[PSCustomObject]@{ .. }`
- 当您构建包含具有不可预测键的项目的 JSON 时，更喜欢使用类似
{items: [{key: 'A', value: 0}, {key: 'B', value: 1}]}over的数组结构{'A': 0, 'B': 1}。后者看起来更直观，但它更难生成，也更难消费。 ConvertFrom-Json()为您提供一个 PowerShell 自定义对象 (PSCustomObject)，它反映 JSON 字符串中的数据。- 您可以循环使用自定义对象的属性
Get-Member -type NoteProperty - 您可以使用
$object."$propName"语法动态访问对象的属性，或者$object."$(some PS expression)". - 您可以创建自己的自定义对象并使用一堆属性对其进行初始化
New-Object PSObject -Property @{...}，或者[PSCustomObject]@{ .. }`
回答by js2010
This question comes up a lot. In this case we have to loop over properties twice. This is my current answer. Make the object a little easier to work with. Both the top level and the data properties become arrays of "name" and "value". You could use select-object calculated properties to present it any way you want. These json examples seem like badly structured objects to me.
这个问题经常出现。在这种情况下，我们必须循环两次属性。这是我目前的答案。使对象更容易使用。顶层和数据属性都变成了“名称”和“值”的数组。您可以使用选择对象计算属性以您想要的任何方式呈现它。这些 json 示例对我来说似乎是结构不良的对象。
$a = cat file.json | convertfrom-json
$a = $a.psobject.properties | select name,value
$a | foreach { $_.value.data =
$_.value.data.psobject.properties | select name,value }
$a.value.data.value
value
-----
{Mr}
{Hyman}
{Cawles}
{Miss}
{Charlotte}
{Tann}
{Mr}
{John}
{Brokland}
Trying something similar with jq:
用 jq 尝试类似的东西：
'{"prop1":1, "prop2":2, "prop3":3}' | jq to_entries | convertfrom-json
key value
--- -----
prop1 1
prop2 2
prop3 3
回答by Alexander Obersht
Here's a simple regex-based solution. Assuming that $sRawJsoncontains your JSON input:
这是一个简单的基于正则表达式的解决方案。假设$sRawJson包含您的 JSON 输入：
$oRegex = [Regex]'(?:(?<="[345]":\{"value"\:\["))[^"]+'
$cParts = $oRegex.Matches(($sRawJson -replace '\s')) | Select-Object -ExpandProperty "Value"
Joining parts to get full names:
加入零件以获得全名：
for ($i = 0; $i -lt $cParts.Count / 3; $i++) { $cParts[($i * 3)..($i * 3 + 2)] -join ' ' }
