Terraform Contains Function [List & String Examples]

In this short article, we will look at the contains function in Terraform, explain what it is and what it does, and share some practical examples using lists and strings. We will then compare it to the strcontains function and share some practical examples. Hope it helps!

1. What is the Terraform contains function?
2. How to use Terraform contains – examples
3. What is Terraform stcontains function?
4. How to use Terraform stcontains – examples

In Terraform, the contains function is used to check if a specified value exists within a given list or set. This function returns true if the value is found and false otherwise. The function is categorized as a ‘collection’ function. The contains function is especially useful when you need to make decisions based on the contents of a list or set.

The syntax of Terraform contains function is as follows:

• list — The list, map, or set to search within.
• value — The value to search for within the list or set.

Read more about Terraform functions, expressions, and loops.

In this example, Terraform contains function is given a list and, after the comma, the value to search for. If the value exists, the function returns true.

Because darth is in the first list, it returns true.

In the second example because jarjar is not in the list, the function returns false.

One good preactical use of the contains function is to check if a particular virtual machine size is supported in a specific Azure region before deploying it.

You can use the contains function to check if the desired VM size is present in the list of available sizes for that region.

Similar to the contains function, the Terraform strcontains function checks whether a substring is within another string. This function is categorized as a ‘String’ function. The strcontains function is useful for string manipulations and conditional logic based on string data.

Syntax of the Terraform strcontains function:

• string — The string to search within for the substring.
• substr — The value to search for within the main string.

In this example, given the first string specified as “darth” we check for the substring within it “dar”. Because it exists, the Terraform stcontains function returns true.

In this second example, we check using the stcontains function for the substring “yoda” within the word “darth”. Because it is not contained within the string, it returns false.

The Terraform contains function is used to check if a specified value exists within a given list or set. And Terraform strcontains function checks whether a substring is within another string.

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Note: New versions of Terraform will be placed under the BUSL license, but everything created before version 1.5.x stays open-source. OpenTofu is an open-source version of Terraform that will expand on Terraform’s existing concepts and offerings. It is a viable alternative to HashiCorp’s Terraform, being forked from Terraform version 1.5.6.