From e6a53387bee66c4315c22354cd5a3edbbb0c6018 Mon Sep 17 00:00:00 2001
From: Andrew Ryan Davis <AndrewDavis1191@gmail.com>
Date: Sun, 16 Aug 2020 21:14:26 -0700
Subject: [PATCH] Addressing comments

1. Clarifying '[]' and null-assigned expressions.
2. Removing "-contains" on switch example from Wouter, it does not appear to be true anymore
3. Adding comments and adjusting some func examples a bit
---
 powershell.html.markdown | 44 ++++++++++++++++++++++++++++++++--------
 1 file changed, 36 insertions(+), 8 deletions(-)

diff --git a/powershell.html.markdown b/powershell.html.markdown
index 7c54dc44..2d4c65b7 100644
--- a/powershell.html.markdown
+++ b/powershell.html.markdown
@@ -149,25 +149,49 @@ $age = 22
 # $null is not an object
 $null  # => None
 
+# $null, 0, and empty strings and arrays all evaluate to False.
+# All other values are True
 # $null, 0, and empty strings and arrays all evaluate to False.
 # All other values are True
 function test ($value) {
-  if ($value) {Write-Output 'True'}
-    else {Write-Output 'False'}
+  if ($value) {
+    Write-Output 'True'
+  }
+  else {
+    Write-Output 'False'
+  }
 }
+
 test ($null) # => False
 test (0)   # => False
 test ("")  # => False
-test []  # => True
+test []  # => True *[] Not valid in Powershell, creates null-valued expression
 test ({})  # => True
 test @()  # => False
 
+<#
+IsPublic IsSerial Name                                     BaseType                                               
+-------- -------- ----                                     --------                                               
+True     True     Int32                                    System.ValueType                                       
+True     True     Int32                                    System.ValueType                                       
+True     True     String                                   System.Object                                          
+You cannot call a method on a null-valued expression.
+At line:4 char:1
++ $test3.getType()
++ ~~~~~~~~~~~~~~~~
+    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
+    + FullyQualifiedErrorId : InvokeMethodOnNull
+ 
+True     True     ScriptBlock                              System.Object                                          
+True     True     Object[]                                 System.Array  
+#>
+
 ####################################################
 ## 2. Variables and Collections
 ####################################################
 
 # Powershell uses the "Write-Output" function to print
-Write-Output "I'm Powershell. Nice to meet you!"  # => I'm Powershell. Nice to meet you!
+Write-Output "I'm Posh. Nice to meet you!"  # => I'm Posh. Nice to meet you!
 
 # Simple way to get input data from console
 $userInput = Read-Host "Enter some data: " # Returns the data as a string
@@ -367,7 +391,6 @@ switch($val) {
   { $_ -like 's*' }       { "Case insensitive"; break }
   { $_ -clike 's*'}       { "clike, ceq, cne for case sensitive"; break }
   { $_ -notmatch '^.*$'}  { "Regex matching. cnotmatch, cnotlike, ..."; break }
-  { 'x' -contains 'x'}    { "FALSE! -contains is for lists!"; break }
   default                 { "Others" }
 }
 
@@ -384,7 +407,6 @@ finally {
 }
 
 
-
 # Writing to a file
 $contents = @{"aa"= 12 
              "bb"= 21}
@@ -532,6 +554,7 @@ True     False    Guitar                                   Instrument
 #>
 
 
+
 ####################################################
 ## 7. Advanced
 ####################################################
@@ -582,7 +605,7 @@ $Area
  This is a silly one
  You may one day be asked to create a func that could take $start and $end
  and reverse anything in an array within the given range
- based on an arbitrary array
+ based on an arbitrary array without mutating the original array
  Let's see one way to do that and introduce another data structure
 #>
 
@@ -599,7 +622,7 @@ function Format-Range ($start, $end) {
         elseif ($index -ge $start -and $index -le $end) {
             $stack.Push($targetArray[$index])
         }
-        elseif ($index -gt $end) {
+        else {
             $secondSectionArray.Add($targetArray[$index]) > $null
         }
     }
@@ -607,6 +630,8 @@ function Format-Range ($start, $end) {
     Write-Output $returnArray
 }
 
+Format-Range 2 6 # => 'a','b','g','f','e','d','c','h','i','j','k','l','m','n'
+
 # The previous method works, but it uses extra memory by allocating new arrays
 # It's also kind of lengthy
 # Let's see how we can do this without allocating a new array
@@ -623,10 +648,13 @@ function Format-Range ($start, $end) {
   }
   return $targetArray
 }
+
+Format-Range 2 6 # => 'a','b','g','f','e','d','c','h','i','j','k','l','m','n'
 ```
 Powershell as a Tool:
 
 Getting Help:
+
 ```Powershell
 # Find commands
 Get-Command about_* # alias: gcm