Windows PowerShell uses a hash table _powershell

A hash table is a pair that is no longer restricted to the use of digital addressing in the hash tables, and can be addressed with any type of data type.

Creating a hash table
Before using @ () to create an array, now use @{} to create a hash table, using the key of the hash table to access the corresponding value.

PS c:powershell> $stu =@{Name = "Xiaoming"; Age= "A" sex= "man"}
PS c:powershell> $stu

name              Value
----              -----
name              xiaoming
Age
Sex              male

PS c:powershell> $stu ["Name"]
xiaoming
PS c:powershell> $stu ["Age"]
PS c:powershell> $stu. Count
3
PS c:powershell> $stu. The Keys
Name age
sex
PS c:powershell> $stu. Values
Xiao
Ming
Man

Storing arrays in a hash table

You can use arrays when you create a hash table, because creating an array and a hash table's element keywords does not conflict. One is a comma and one is a semicolon.

PS c:powershell> $stu =@{Name = "Xiaoming"; "Age="; sex= "male"; Books= "The Kingdoms", "Siege", "Hamlet"}
PS c:powershell> $stu

Name              Value
---------Books {The             kingdoms of the , Fortress besieged, Hamlet
}              Name
xiaoming
sex              male

Inserts a new key value in the hash table

Inserting a new key value in a hash table is convenient, like defining a variable, which you can use directly to

PS c:powershell> $Student =@{}
PS c:powershell> $Student. name= "make Fox Dash"
PS c:powershell> $ Student.school= "Huashan pie"
PS c:powershell> $Student

name              Value
----              -----
name              Make Fox Chong
School             Huashan Pie

Update and delete of hash table values

If you want to update the value of a key, you can override it directly. If you want to remove this key-value pair, you can use the Remove method, which is the key

PS c:powershell> $stu

name              Value
----              -----
Books             {The kingdoms, Siege, Hamlet}
name              xiaoming
Age
Sex              male

PS c:powershell> $stu. Name= "Qiang Zhao"
PS c:powershell> $stu. Name
Qiang Zhao
PS c:powershell> $stu. Remove ("Name")
PS c:powershell> $stu

Name              Value
----              -----
Books             {The kingdoms, the siege, Hamlet}
age
Sex              male

Format output using a hash table

An interesting application of a hash table in PowerShell can be used to format text output. PowerShell the output of many commands is in tabular form, and of course you can use format-table to customize the table format, for example:

PS c:powershell> Dir | Format-table

  Directory:c:powershell

Mode        lastwritetime   Length Name
----        -------------   ----------
d----    2011/11/23   17:25      ABC
d----    2011/11/29   18:21      MyScript

PS c:powershell> Dir | Format-table fullname,mode

FullName                          Mode
--------                          ----
c:powershellabc                      d----
c:powershellmyscript                   d----
c:powershella.html-a                    ---

The above commands only limit the columns that the table outputs, and hide those columns. But for the width of the column, the column headers are powerless, but with a hash table you can implement more customizations.
Each column of a table contains four properties:
Expression: Bound expression
Width: Column widths
Label: Column headings
Alignment: How columns are aligned

PS c:powershell> $column 1 = @{expression= "Name"; width=30;label= "filename"; alignment= "left"
PS C:powershell > $column 2 = @{expression= "LastWriteTime"; width=40;label= "last Modification" alignment= "right"
PS C: Powershell> ls | Format-table $column 1, $column 2

filename last                       modification
--------                       -----------------
ABC                         2011/11/23 17:25:53
myscript                      2011/11/29 18:21:28
a.html                       2011/11/24 18:30:13