Array.from

Question

我在这里很迷茫。给定一个数字n，我必须返回一个用值null填充的n * n嵌套数组。如果n是3：

[
  [null, null, null],
  [null, null, null],
  [null, null, null]
]

我很迷茫。我有这样的事情：

function generateMatrix (n) {
  let item = 'null';
  let array1 = [];
  let solution = [];
  array1.push(item.repeat(n));
  solution.push(array1.repeat(n));
  return solution;  
  }

我知道这是不对的，不仅因为它不起作用，而且因为它没有意义，我不知道该怎么做。请记住，我非常非常初级，刚开始学习JS。

我见过other similar个帖子，但无法理解。

提前致谢。

Answer 1

您可以使用Array.from和Array.fill方法执行此操作。

function matrix(n) {
  return Array.from(Array(n), () => Array(n).fill(null))
}

console.log(matrix(3))

您可以使用相同的方法创建尺寸为rows x columns的矩阵。

function matrix(rows, cols) {
  return Array.from(Array(rows), () => Array(cols).fill(null))
}

console.log(matrix(2, 4))
console.log(matrix(3, 2))

Answer 2

$MaxThread = 10
$RunspacePool = [runspacefactory]::CreateRunspacePool(
    [System.Management.Automation.Runspaces.InitialSessionState]::CreateDefault()
)
[void]$RunspacePool.SetMaxRunspaces($MaxThread)
$RunspacePool.Open()

$UserCredential = Get-Credential

Import-Module ActiveDirectory


$Users = Get-ADUser -filter * -Properties * -SearchBase "OU=Disabled User Accounts,DC=private,DC=private"

$Today = (Get-Date).ToShortDateString()
$OneMonthAgo = (Get-Date).AddMonths(-1).ToShortDateString()

[Collections.ArrayList]$results = @()    

$OnPrem = $Users | Where-Object {$_.mDBUseDefaults -eq "True"}
$365 = $Users | Where-Object{$_.mDBUseDefaults -ne "True"}

Write-Host "Start Date: " $OneMonthAgo -ForegroundColor Green
Write-Host "Total Users OnPrem: " ($OnPrem.mail).Count -ForegroundColor Green


$OnPremScriptblock = {
    Param (
        [System.Management.Automation.PSCredential]$Credential,
        [string]$emailAddress,
        [string]$startTime,
        [string]$userName,
        [string]$loginName,
        [string]$DisabledDate,
        [string]$OfficeLocation
    )      

    $Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri http://aserversomewhere.local/PowerShell/ -Authentication Kerberos -Credential $Credential
    Import-PSSession $Session -AllowClobber -DisableNameChecking -Verbose:$false | Out-Null

    $MessageCount = Get-MessageTrackingLog -recipients $emailAddress -Start $startTime.ToString() -ResultSize unlimited  

    $Object = New-Object PSObject -Property @{
        User = $userName
        Login = $loginName
        Email = $emailaddress
        Type = "OnPrem"
        DisabledDate = $DisabledDate
        Location = $OfficeLocation
        MessagesReceived = $MessageCount.Count.ToString()
        }           

     $Object


}

$jobs = New-Object System.Collections.ArrayList
foreach ($user in $OnPrem){

    $PowerShell = [PowerShell]::Create()

    $null = $PowerShell.AddScript($OnPremScriptblock)
    $null = $PowerShell.AddArgument($UserCredential)
    $null = $PowerShell.AddArgument($user.mail)
    $null = $PowerShell.AddArgument($OneMonthAgo)
    $null = $PowerShell.AddArgument($user.name)
    $null = $PowerShell.AddArgument($user.samaccountname)
    $null = $PowerShell.AddArgument($user.modified)
    $null = $PowerShell.AddArgument($user.Office)

    $PowerShell.RunspacePool = $RunspacePool

    [void]$jobs.Add((
    [pscustomobject]@{
        PowerShell = $PowerShell
        Handle = $PowerShell.BeginInvoke()
    }
    ))
}

While($jobs.handle.IsCompleted -eq $false){
    Write-Host "." -NoNewline
    Start-Sleep -Milliseconds 100
}

$return = $jobs | foreach{
    $_.PowerShell.EndInvoke($_.Handle)
    $_.PowerShell.Dispose()
}
$jobs.Clear()
$return

Answer 3

这是使用 Array.from 功能和 fill 功能的替代选择。

Rewind

var rows = 3;
var cols = 3;

var matrix = Array.from({length: rows}, () => new Array(cols).fill(null))
console.log(JSON.stringify(matrix, null, 2));

Array.from

.as-console-wrapper { max-height: 100% !important; top: 0; }可让您从：
创建数组

类似数组的对象（具有 Array.from() 属性和索引元素的对象）或

可迭代对象（可以获取其元素的对象，例如Map和Set）。

返回一个用null填充的n * n嵌套数组

3 个答案:

Array.from