<\/p>\n
John Smith asked what TRUE and FALSE were in PowerShell on our newsgroup Microsoft.Public.Windows.PowerShell. The simple answer to this is $TRUE and $FALSE but the complete answer is a richer. PowerShell has a very rich notion of TRUE and FALSE. The best way to explain it is to show it. <\/span><\/p>\n PS> function test ($VALUE) { The question a lot of PowerShell newbies ask is: \u2018Why is \u201cFALSE\u201d TRUE?\u201d In PowerShell, Strings can be evaluated as Booleans. If a string is ZERO length \u2013 it is false, otherwise it is TRUE. \u201cFALSE\u201d has 5 characters so it is TRUE.<\/p>\n PS> test “SHORT STRING” Given that see if you can figure out what is going on with the sequence below:<\/p>\n PS> test “0” \u201c0\u201d is TRUE because it is a STRING and it has a length of 1. 0 is FALSE because it is a number and that number is 0. In PowerShell, any number which evaluates to 0 is FALSE and every non-zero number is TRUE. The example shows you a floating point zero, a hexadecimal zero, 0 megs, 0 kilos, 0 decimal, there are all sorts of zeros but to PowerShell, they all evaluate to FALSE. <\/p>\n The next one should be a little easier to figure out. The last 2 lines shows you what you would have to type if we didn\u2019t have a rich concept of TRUE and FALSE. <\/p>\n PS> $x=@(1,2,3,4,5) Here is your last example. If a variable is defined, we use its value to determine TRUE\/FALSE but if the variable is not defined \u2013 it is FALSE.<\/p>\n PS> $x=10 PowerShell has a rich notion of TRUE\/FALSE because it dramatically reduces the overhead and junk that you need to deal with when doing your work.<\/p>\n Happy Holidays!<\/p>\n Jeffrey Snover [MSFT] John Smith asked what TRUE and FALSE were in PowerShell on our newsgroup Microsoft.Public.Windows.PowerShell. The simple answer to this is $TRUE and $FALSE but the complete answer is a richer. PowerShell has a very rich notion of TRUE and FALSE. The best way to explain it is to show it. PS> function test ($VALUE) {>> […]<\/p>\n","protected":false},"author":600,"featured_media":13641,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-9051","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-powershell"],"acf":[],"blog_post_summary":" John Smith asked what TRUE and FALSE were in PowerShell on our newsgroup Microsoft.Public.Windows.PowerShell. The simple answer to this is $TRUE and $FALSE but the complete answer is a richer. PowerShell has a very rich notion of TRUE and FALSE. The best way to explain it is to show it. PS> function test ($VALUE) {>> […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/posts\/9051","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/users\/600"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/comments?post=9051"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/posts\/9051\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/media\/13641"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/media?parent=9051"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/categories?post=9051"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/tags?post=9051"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
>> if ($VALUE) {
>> Write-Host -ForegroundColor GREEN “TRUE”
>> } else {
>> Write-Host -ForegroundColor RED “FALSE”
>> }
>> }
>>
PS> test $TRUE
TRUE<\/span>
PS> test $FALSE
FALSE<\/span>
PS> test TRUE
TRUE<\/span>
PS> test FALSE
TRUE<\/span><\/p>\n
TRUE<\/span>
PS> test “”
FALSE<\/span>
PS> $x=(” ” -replace ” “)
PS> test $x
FALSE<\/span>
PS><\/p>\n
TRUE<\/span>
PS> test 0
FALSE<\/span>
PS> test 1
TRUE<\/span>
PS> test 0.0
FALSE<\/span>
PS> test 0x0
FALSE<\/span>
PS> test 0mb
FALSE<\/span>
PS> test 0kb
FALSE<\/span>
PS> test 0D
FALSE<\/span>
PS> test 0.00000001
TRUE<\/span>
PS><\/p>\n
PS> test $x
TRUE<\/span>
PS> $x=@()
PS> test $x
FALSE<\/span>
PS> test (get-Process)
TRUE<\/span>
PS> test (get-Process |where {$_.name -eq “PowerShell”})
TRUE<\/span>
PS> test (get-Process |where {$_.name -eq “NoSuchProcess”})
FALSE<\/span>
PS> test (@(get-Process |where {$_.name -eq “PowerShell”}).count -ne 0)
TRUE<\/span>
PS> test (@(get-Process |where {$_.name -eq “NoSuchProcess”}).count -ne 0)
FALSE<\/span><\/p>\n
PS> test $x
TRUE
<\/span>PS> $x=0
PS> test $x
FALSE<\/span>
PS> test $NoSuchVariable
FALSE<\/span>
PS> set-psdebug -strict
PS> $NoSuchVariable
The variable $NoSuchVariable cannot be retrieved because it has not been se
t yet.
At line:1 char:15
+ $NoSuchVariable <<<<<\/span>
PS><\/p>\n
Windows PowerShell\/MMC Architect
Visit the Windows PowerShell Team blog at: http:\/\/blogs.msdn.com\/PowerShell
Visit the Windows PowerShell ScriptCenter at: http:\/\/www.microsoft.com\/technet\/scriptcenter\/hubs\/msh.mspx<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"