Variables & Arrays & Hash Table/Dict.

• case-insensitive

Functions explained in following Format:

$var.Func() -> output

---

🔤 STRING (System.String)

$str ="  Hello World  "

$str.Trim()->"Hello World"
$str.ToUpper() ->"  HELLO WORLD  "
$str.ToLower() ->"  hello world  "
$str.Replace("World","PowerShell") ->"  Hello PowerShell  "
$str.Substring(2,5) ->"Hello"
$str.Contains("Hello") -> True
$str.StartsWith("  He") -> True
$str.EndsWith("  ") -> True
$str.IndexOf("World") ->8
$str.Split(" ") -> {"","","Hello","World","",""}

---

🔢 NUMBERS (Int / Double)

$num =-15.7

$num.ToString() -> "-15.7"
$num.GetType() -> Double
[Math]::Abs($num) -> 15.7
[Math]::Round($num) -> -16
[Math]::Ceiling($num) -> -15
[Math]::Floor($num) -> -16
[Math]::Pow(2,3) -> 8
[Math]::Sqrt(16) -> 4
[Math]::Max(5,9) -> 9
[Math]::Min(5,9) -> 5

---

📚 ARRAY (System.Array)

$arr =1,2,3,4,5

$arr.Count -> 5
$arr.Length -> 5
$arr.GetType() -> Object[]
$arr.Contains(3) -> True
$arr.IndexOf(4) -> 3
$arr.Clone() -> {1,2,3,4,5}
$arr.Reverse() -> {5,4,3,2,1}
$arr.Clear() -> {}

---

🗂 HASHTABLE (System.Collections.Hashtable)

$hash = @{Name="John"; Age=30}

$hash.Keys -> Name, Age
$hash.Values -> John, 30
$hash.ContainsKey("Name") -> True
$hash.ContainsValue(30) -> True
$hash.Add("City","NY") -> Adds new key
$hash.Remove("Age") -> Removes Age
$hash.Count -> 2
$hash.Clear() -> {}
$hash.GetType() -> Hashtable

---

📅 DATETIME (System.DateTime)

$date =Get-Date

$date.ToShortDateString() -> 2/19/2026
$date.ToLongDateString() -> Thursday, February 19, 2026
$date.AddDays(5) -> (date + 5 days)
$date.AddMonths(1) -> (date + 1 month)
$date.AddYears(1) -> (date + 1 year)
$date.Day -> 19
$date.Month -> 2
$date.Year -> 2026
$date.DayOfWeek -> Thursday
$date.ToString("yyyy-MM-dd") -> 2026-02-19

---

📦 PSCUSTOMOBJECT

$obj = [PSCustomObject]@{Name="Alice"; Score=95}

$obj.GetType() -> PSCustomObject
$obj.PSObject.Properties.Name -> Name, Score
$obj | Get-Member -> Shows members
$obj.ToString() -> @{Name=Alice; Score=95}

Arrays and Hash Table/Dict.

• arrays are fixed size just like in .NET
• to modify array we have to create a new one and copy all from old and add new element..

PS C:\Users\PavanKumarBandaru\Desktop> [string[][]]$a2 = @(
>>     ("Pavan","Hari","Siva"),
>>     ("Apple","Banana","Orange")
>> )
PS C:\Users\PavanKumarBandaru\Desktop> $a2[0]
Pavan
Hari
Siva
PS C:\Users\PavanKumarBandaru\Desktop> $a2[0][0]
Pavan