In my last post I looked at some Comparison Operators. Now I will examine some more Comparison Operators.

Greater than and Less than operators

The greater than operator (-gt) returns a value of TRUE or the matches when one or more of the input values is greater than the specified pattern. The less than operator (-lt) returns a value of TRUE or the matches when one or more of the input values is less than the specified pattern. When the ‘or equals to’ operators (-ge, -le) are used, they also compare to see if the value is equal to the specified pattern.

The following examples show the effects of these operators.

8 -gt 7

Containment Operators

The containment operators (-contains and -notcontains) are similar to the equality operators. However, the containment operators always return a Boolean value, even when the input is a collection.

Also, unlike the equality operators, the containment operators return a value as soon as they detect the first match. The equality operators evaluate all input and then return all the matches in the collection. In a very large collection, the -contains operator returns results quicker than the equal to operator. The following examples show the effect of the -contains operator.

1, 2, 3 -contains 2

In my next post we will finish looking at Comparison Operators.

In my last post I looked at Assignment Operators. Now I will examine Comparison Operators.

Comparison operators let you specify conditions for comparing values and finding values that match specified patterns. To use a comparison operator, specify the values that you want to compare together with an operator that separates these values.

By default, all comparison operators are case-insensitive. To make a comparison operator case-sensitive, precede the operator name with a "c". For example, the case-sensitive version of "-eq" is "-ceq". To make the case-insensitivity explicit, precede the operator with an "i". For example, the explicitly case-insensitive version of "-eq" is "ieq".

All comparison operators except the containment operators (-contains, -notcontains) and type operators (-is, -isnot) return a Boolean value when the input to the operator (the value on the left side of the operator) is a single value (a scalar). When the input is a collection of values, the containment operators and the type operators return any matching values. If there are no matches in a collection, these operators do not return anything. The containment operators and type operators always return a Boolean value.

Windows PowerShell supports the following comparison operators.

Equality Operators

The equality operators (-eq, -ne) return a value of TRUE or matches when one or more of the input values is identical to the specified pattern. The entire pattern must match an entire value.

The following examples show the effect of the equal to operator:

"a" -eq "A"

"a" -ceq "A"

1, 2, 3 -eq 2

"Power" -ne "Shell"

In my next post we will examine more Comparison Operators.

In my last post I reviewed Arithmetic Operators. Now I will explore Assignment Operators.

Assignment operators assign one or more values to a variable and perform numeric operations on the values before the assignment. Windows PowerShell supports the following assignment operators.

The assignment operator (=) assigns values to variables. If the variable already has a value, the assignment operator (=) replaces the value without warning. Since the assignment operator has been mentioned multiple times in this training, no additional details are included here.

The assignment by addition, subtraction, multiplication, and division operators all work more or less the same way. For numeric types it takes the first part of the operator (+, -, *, /) and performs the appropriate calculation and then it assigns the result. For strings, it appends the specified value to the existing value. The assignment by subtraction and division operators do not work with strings. Let’s take a closer look at several of these operators.

The assignment by addition operator (+=) either increments the value of a variable or appends the specified value to the existing value. The action depends on whether the variable has a numeric or string type and whether the variable contains a single value (a scalar) or multiple values (a collection). First, it adds, and then it assigns.

$a = 5

$a += 2

$a

When the value of the variable is a string, the value on the right side of the operator is appended to the string.

$a = "String"

$a += ” Appended”

$a

The assignment by subtraction operator (-=) decrements the value of a variable by the value that is specified on the right side of the operator. This operator cannot be used with string variables and it cannot be used to remove an element from a collection. First, it subtracts, and then it assigns.

$a = 5

$a -= 2

$a

The increment operator (++) increases the value of a variable by 1. When you use the increment operator in a simple statement, no value is returned.

$a = 6

++$a

$a

The decrement operator (–) decreases the value of a variable by 1. As with the increment operator, no value is returned when you use the operator in a simple statement. Use parentheses to return a value.

$a = 6

(–$a)

In my next post we will examine Comparison Operators.