$str4=" "if($str4-match"^\s*$") {Write-Host"String is empty"}else{Write-Host"String is not empty"} 输出: String is empty
Checking if a string is NULL or EMPTY is very common requirement in Powershell script. If we don’t do that we will end up with run time errors if we try to perform some operation on that string variable which is empty or null. So the question now is, how to check it? Well, belo...
ValidateNotNullAttribute 例子 ValidateNotNullOrEmptyAttribute 例子,注意@()为一个空数组。
[Parameter(Position = 0)] [ValidateNotNullOrEmpty] public string[] Name 重写输入处理方法 如果cmdlet 要处理命令行输入,则必须重写相应的输入处理方法。 创建第一个 Cmdlet中引入了基本输入处理方法。 Get-Proc cmdlet 重写 System.Management.Automation.Cmdlet.ProcessRecord 方法来处理用户或脚本提...
if($PSBoundParameters.ContainsKey('Value') ){...} IsNotNullOrEmpty 如果值为字符串,则可以同时使用静态字符串函数来检查值为$null还是空字符串。 PowerShell if(-not[string]::IsNullOrEmpty($value) ){...} 当我知道值类型应该是字符串时,我经常使用此值。
$string=""if($string) {Write-Host"The variable is not null."}else{Write-Host"The variable is null." } Output: The variable is null. White space characters are not considered null string values. Use theIsNullorEmptyMethod to Check if a String Variable Is Not Null or Empty in PowerShell...
~/.bash_profile"$content=(Get-Content"$file"-ErrorAction Ignore-Raw)+[System.String]::Empty ...
Value '' is an empty string Value [5] isn't an empty string or $null Value '' is $null 在switch语句中测试是否有空字符串时,请务必使用比较语句(如本示例所示),而不是原始值''。 在switch语句中,原始值''也与$null匹配。 例如: PowerShell ...
You can also specify thatSelect-Stringshould expect a particular character encoding, such as when you're searching files of Unicode text.Select-Stringuses the byte-order-mark (BOM) to detect the encoding format of the file. If the file has no BOM, it assumes the encoding is UTF8. ...
Stringify ErrorRecord with empty exception message to empty string (#24949) (Thanks @MatejKafka!) Add completion single/double quote support for -PSEdition parameter for Get-Module (#24971) (Thanks @ArmaanMcleod!) Error when New-Item -Force is passed an invalid directory name (#24936) (Than...