terraform/website/docs/configuration/expressions.html.md

---
layout: "language"
page_title: "Expressions Landing Page - Configuration Language"
sidebar_current: "docs-config-expressions"
---

# Expressions Landing Page

To improve navigation, we've split the old Expressions page into several smaller
pages.

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## Types and Values, Literal Expressions, Indices and Attributes

Terraform's types are `string`, `number`, `bool`, `list`, `tuple`, `map`,
`object`, and `null`.

This information has moved to
[Types and Values](/docs/configuration/expressions/types.html).

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## References to Named Values (Resource Attributes, Variables, etc.)

You can refer to certain values by name, like `var.some_variable` or
`aws_instance.example.ami`.

This information has moved to
[References to Values](/docs/configuration/expressions/references.html).

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## Arithmetic and Logical Operators

Operators are expressions that transform other expressions, like adding two
numbers (`+`) or comparing two values to get a bool (`==`, `>=`, etc.).

This information has moved to
[Operators](/docs/configuration/expressions/references.html).

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## Conditional Expressions

The `condition ? true_val : false_val` expression chooses between two
expressions based on a bool condition.

This information has moved to
[Conditional Expressions](/docs/configuration/expressions/conditionals.html).

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## Function Calls

Terraform's functions can be called like `function_name(arg1, arg2)`.

This information has moved to
[Function Calls](/docs/configuration/expressions/function-calls.html).

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## `for` Expressions

Expressions like `[for s in var.list : upper(s)]` can transform a complex type
value into another complex type value.

This information has moved to
[For Expressions](/docs/configuration/expressions/for.html).

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## Splat Expressions

Expressions like `var.list[*].id` can extract simpler collections from complex
collections.

This information has moved to
[Splat Expressions](/docs/configuration/expressions/splat.html).

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## `dynamic` Blocks

The special `dynamic` block type serves the same purpose as a `for` expression,
except it creates multiple repeatable nested blocks instead of a complex value.

This information has moved to
[Dynamic Blocks](/docs/configuration/expressions/dynamic-blocks.html).

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## String Literals and String Templates

Strings can be `"double-quoted"` or

```hcl
<<EOT
heredocs
EOT
```

Strings can also include escape sequences like `\n`, interpolation sequences
(`${ ... }`), and template sequences (`%{ ... }`).

This information has moved to
[Strings and Templates](/docs/configuration/expressions/strings.html).

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