如何一次检查哈希表键和值是否存在空/空/空格

Question

当我想在 PowerShell 脚本的条件下一次检查所有这些内容时：

1. 检查是否存在哈希表密钥
2. 检查键值是否为NULL
3. 检查键值是否为空字符串
4. 检查键值不仅仅是空格

我是这样做的：

$properties = @{ first = 'A'; second = ''; third = 'C' }

if (![string]::IsNullOrWhitespace($properties.first)) {
    Write-Host "Value of key 'first' is: $($properties.first)"
}
if (![string]::IsNullOrWhitespace($properties.second)) {
    Write-Host "Value of key 'second' is: $($properties.second)"
}
if (![string]::IsNullOrWhitespace($properties.fourth)) {
    # This does not fail 
}

输出:

Value of key 'first' is: A

显然，它甚至适用于不存在的钥匙。但是我很好奇是否有更好或更干净的方法来做到这一点？

Answer 1

只是为了说明安斯加的好建议:

$properties = @{ first = 'A'; second = ''; third = 'C' }

ForEach ($key in "first","second","fourth") {
    if (([string]$properties[$key]).Trim()) {
        Write-Host ("Value of key '{0}' is: {1}" -f $key,$properties[$key])
    } else {
        Write-Host ("Either key '{0}' is not existent or value is empty/Null" -f $key)
    }
}

示例输出：

Value of key 'first' is: A
Either key 'second' is not existent or value is empty/Null
Either key 'fourth' is not existent or value is empty/Null