Powershell - if($variable) 测试什么? [英] Powershell - What does if($variable) test for?

问题描述

在 Powershell 中，if($variable) 测试什么?这是测试变量是否已设置、为空、为真还是其他?

In Powershell, what does if($variable) test for? Is this testing if the variable is set, is null, is true, or something else?

推荐答案

它测试变量是否为真或非布尔变量是否可以合并为真.例如，每个都返回 false:

It tests whether the variable is true or whether a non-Boolean variable can be coalesced to true. For example, each of these return false:

$var #uninitialized
$var = ""
$var = $false
$var = 0

这些都返回真:

$var = "something"
$var = $true
$var = 1 #or any non-zero number

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