# tencent cloud

### Expression

Last updated: 2022-01-14 14:30:41

## Operators

Operators are used for arithmetic or logical operations.

### Arithmetic operators

• a + b: returns the result of adding `a` and `b` together.
• a - b: returns the result of subtracting `b` from `a`.
• a * b: returns the result of multiplying `a` and `b`.
• a / b: returns the result of dividing `a` by `b`.
• a % b: returns the remainder of dividing `a` by `b`. This operator is generally useful only when used with whole numbers.
• -a: returns the result of multiplying `a` by -1.

### Comparison operators

• a == b: returns `true` if `a` and `b` both have the same type and the same value, or `false` otherwise.
• a != b: is the opposite of `a == b`.
• a < b: returns `true` if `a` is less than `b`, or `false` otherwise.
• a > b: returns `true` if `a` is greater than `b`, or `false` otherwise.
• a <= b: returns `true` if `a` is less than or equal to `b`, or `false` otherwise.
• a >= b: returns `true` if `a` is greater than or equal to `b`, or `false` otherwise.

### Logical operators

• a || b: returns `true` if either `a` or `b` is `true`, or `false` if both are `false`.
• a && b: returns `true` if both `a` and `b` are `true`, or `false` if either one is `false`.
• !a: returns `true` if `a` is `false`, or `false` if `a` is `true`.

## Conditional Expression

A conditional expression uses the value of a Boolean expression to select one of two values. For example:

``````condition ? one_value : two_value
``````

## for Expression

A `for` expression can be used to traverse a set of collections and map one collection type to another. For example:

``````[for item in items : upper(item)]
``````

## Expanded Expression

An expanded expression is a concise expression similar to a `for` expression. For example:

``````[for o in var.list : o.id]
is equivalent to
var.list[*].id
``````

## Function Expression

Terraform supports the use of some built-in functions when expressions are calculated. An expression to call a function is similar to an operator. For example:

``````upper("123")
``````