String functions (LEFT, RIGHT, CONTAINS) in Tableau - Step-by-Step Guide

Introduction

String functions help you work with text data by extracting parts or checking if text contains certain words. This makes it easier to clean, filter, or analyze text in your reports.

When you want to show only the first few letters of a product code to group similar items.

When you need to check if customer comments mention a specific word like 'refund'.

When you want to extract the last few characters from an ID to identify a region or category.

When filtering sales data to include only records where the product name contains 'Pro'.

When creating a new field that shows a short version of a long text description.

Steps

Step 1: Open Tableau and connect to your data source

- Data Source tab

Your data fields appear in the Data pane on the left

Step 2: Create a calculated field

- Data pane, right-click and select 'Create Calculated Field...'

A calculation editor window opens

Step 3: Type the LEFT function formula

- Calculation editor

The formula extracts the first characters from a string

💡 Example: LEFT([Product Name], 3) returns the first 3 letters of Product Name

Step 4: Click OK to save the calculated field

- Calculation editor

The new field appears in the Data pane

Step 5: Repeat steps 2-4 using RIGHT function

- Calculation editor

RIGHT([Order ID], 4) extracts the last 4 characters of Order ID

Step 6: Create a calculated field using CONTAINS function

- Calculation editor

CONTAINS([Comments], 'refund') returns TRUE if 'refund' is in Comments

Step 7: Use these calculated fields in your worksheet

- Rows or Columns shelf or Filters pane

Your visualization updates based on the extracted or filtered text

Before vs After

Before

Product Name column shows full names like 'ProMax 3000', 'Basic Model', 'ProLite'

After

Calculated field with LEFT([Product Name], 3) shows 'Pro', 'Bas', 'Pro' to group products by prefix

Settings Reference

LEFT function

📍 Calculation editor

Extracts the first N characters from a text string

Default: No default, you specify the number of characters

RIGHT function

📍 Calculation editor

Extracts the last N characters from a text string

Default: No default, you specify the number of characters

CONTAINS function

📍 Calculation editor

Checks if a text string contains a specific substring, returns TRUE or FALSE

Default: No default, you specify the substring to find

Common Mistakes

Using LEFT or RIGHT without specifying the number of characters

Tableau requires the number of characters to extract; missing it causes errors

Always include the number of characters, e.g., LEFT([Field], 4)

Using CONTAINS with case-sensitive text expecting case-insensitive match

CONTAINS is case-sensitive, so 'Refund' and 'refund' are different

Use LOWER() function to convert both strings to lowercase, e.g., CONTAINS(LOWER([Comments]), 'refund')

Summary

String functions LEFT, RIGHT, and CONTAINS help extract or check parts of text data.

They are useful for grouping, filtering, or cleaning text fields in Tableau.

Remember to specify the number of characters for LEFT and RIGHT, and handle case sensitivity with CONTAINS.