英文:

comparing integer with multiple conditions in powershell

问题 {#heading}

抱歉，我只能回答你的翻译请求。以下是翻译好的内容：

抱歉对于这个"愚蠢"的问题，但我要疯了！我需要理解一个变量是否存在，如果存在的话，还要检查它的值是否不是0。我可以使用多个条件，还是必须使用多个语句像是elseif呢？

[int]$AllDbAvail = 0 #(在这种情况下，我已经定义了变量)
[int]$int0 = 0
if ( ( Test-Path variable:AllDbAvail ) -or ( $AllDbAvail -ne $int0 ) ) {"ok"} else {"not ok"}

输出：

PS > not ok

另一个使用 @Mathias 方法的测试：

Remove-Variable AllDbAvail
if ( ( Test-Path variable:AllDbAvail ) -and ( $AllDbAvail -ne $int0 ) ) {"ok"} else {"not ok"}

输出：

not ok
`[int]$AllDbAvail = 0
if ( ( Test-Path variable:AllDbAvail ) -and ( $AllDbAvail -ne $int0 ) ) {"ok"} else {"not ok"}
`

输出：

not ok

$PSVersionTable.PSVersion

主要  次要  构建   修订
-----  -----  -----  --------
5      1      17763  3770

也尝试过：

主要  次要  补丁  预发行标签   构建标签
-----  -----  -----  --------------- ----------
7      2      1

结果相同。

对于PowerShell来说，"数字0"并不是一个值！或者更确切地说，在某些情况下才是一个值！

并且，如果需要将数字0作为字符串表示，可以在没有[int]前缀的情况下创建一个int，需要用双引号 "0" 表达：

英文:

Sorry for the "stupid" question but I'm going crazy!
I need to understand if a variable exist and, if exist, checking also if its value isn't 0.
I can use multiple conditions, or I've to use multiple statements like elseif?

[int]$AllDbAvail = 0 #(in this case I've defined variable)
[int]$int0 = 0
if ( ( Test-Path !variable:AllDbAvail ) -or ( $AllDbAvail -ne $int0 ) ) {"ok"} else {"not ok"}
`PS >not ok
`

Another test with @Mathias approch:

PS >  Remove-Variable AllDbAvail
PS > if ( ( Test-Path variable:AllDbAvail ) -and ( $AllDbAvail -ne $int0 ) ) {"ok"} else {"not ok"}
not ok
PS > [int]$AllDbAvail = 0
PS > if ( ( Test-Path variable:AllDbAvail ) -and ( $AllDbAvail -ne $int0 ) ) {"ok"} else {"not ok"}
not ok

$PSVersionTable.PSVersion

Major  Minor  Build  Revision


*** ** * ** ***


`5      1      17763  3770
`

tried also on:

Major  Minor  Patch  PreReleaseLabel BuildLabel
-----  -----  -----  --------------- ----------
7      2      1

Same result.

For powershell "number 0" isn't a value! Or better, is a value only in certain circumstances!

And an int can be created without the [int] prefix, if number 0 have to be a string needs to be expressed with double quotes "0":

答案1 {#1}

得分: 1

需要从变量提供程序路径中删除 ! 并将 -or 更改为 -and：

if ((Test-Path variable:AllDbAvail) -and ($AllDbAvail -ne 0)) {
  "ok"
}
else {
  "not ok"
}

话虽如此，需要测试变量的存在有点不太合适 - 你可能需要重新考虑你的方法

正如Nico在评论中指出的，你可以大大简化条件：

if ($AllDbAvail) {
  "ok"
}
else {
  "not ok"
}

一个未被赋值的变量将评估为 $null - 而 $null 和整数值 0 都将在转换为布尔值时评估为 $false。

关于你的 "second test"，我不太确定要说什么 - 它的行为正如预期的那样。

你尝试指定一个非零值了吗？

英文:

You need to remove ! from the variable provider path and change -or to -and:

if ((Test-Path variable:AllDbAvail) -and ($AllDbAvail -ne 0)) {
  "ok"
}
else {
  "not ok"
}

That being said, having to test for the existence of a variable is a bit of a code smell - you might want to rethink your approach

As Nico points out in the comments, you can simplify the condition significantly:

if ($AllDbAvail) {
  "ok"
}
else {
  "not ok"
}

A variable that hasn't been assigned to will evaluate to $null - and both $null and the integer value 0 will in turn evaluate to $false when converted to a boolean.

With regards to your "second test", I'm not really sure what to say - it's behaving exactly as expected.

Did you try specifying a non-zero value?