Why String functions (LEFT, RIGHT, CONTAINS) in Tableau? - Purpose & Use Cases

The Big Idea

What if you could find and extract exactly the text you need in seconds, not hours?

The Scenario

Imagine you have a long list of customer names and emails in a spreadsheet. You need to find all customers whose email ends with '@gmail.com' or extract the first three letters of their names to create a quick code. Doing this by scanning each row manually or copying and pasting is exhausting and slow.

The Problem

Manually searching through thousands of rows is error-prone and takes hours. Copying parts of text by hand leads to mistakes, and filtering emails without automation means you might miss important data or waste time repeating the same steps.

The Solution

String functions like LEFT, RIGHT, and CONTAINS in Tableau let you quickly extract parts of text or check if certain words or characters exist in your data. This automation saves time, reduces errors, and helps you focus on analyzing results instead of preparing data.

Before vs After

✗ Before

Scan each cell, copy first 3 letters manually
Filter emails by reading each one

✓ After

LEFT([Name], 3)
CONTAINS([Email], "@gmail.com")

What It Enables

With these string functions, you can instantly clean, filter, and categorize text data to uncover insights faster and more accurately.

Real Life Example

A marketing analyst uses CONTAINS to find all customers with emails from a specific domain to target a campaign, and LEFT to create short customer codes for quick reference.

Key Takeaways

Manual text handling is slow and error-prone.

String functions automate text extraction and searching.

They help you analyze data faster and with confidence.

Practice

1. What does the Tableau function LEFT('Tableau', 3) return?

easy

A. 'Tab'

B. 'bleau'

C. 'Table'

D. 'au'

Solution

1. Step 1: Understand LEFT function

   The LEFT function extracts characters from the start of a string. Here, it extracts 3 characters from 'Tableau'.

2. Step 2: Extract first 3 characters

   The first 3 characters of 'Tableau' are 'Tab'.

3. Final Answer:

   'Tab' -> Option A

4. Quick Check:

   LEFT('Tableau', 3) = 'Tab' [OK]

Hint: LEFT gets characters from the start of text [OK]

Common Mistakes:

• Confusing LEFT with RIGHT function
• Extracting more or fewer characters than specified
• Assuming it extracts from the end

2. Which of the following is the correct syntax to check if the string 'Data' contains the letter 'a' in Tableau?

easy

A. LEFT('Data', 'a')

B. CONTAINS('Data', 'a')

C. CONTAINS('a', 'Data')

D. RIGHT('Data', 'a')

Solution

1. Step 1: Understand CONTAINS syntax

   CONTAINS(text, substring) checks if substring exists in text. The first argument is the main text, second is what to find.

2. Step 2: Apply to given strings

   To check if 'Data' contains 'a', use CONTAINS('Data', 'a').

3. Final Answer:

   CONTAINS('Data', 'a') -> Option B

4. Quick Check:

   CONTAINS('Data', 'a') = TRUE [OK]

Hint: CONTAINS(text, substring) order matters: text first [OK]

Common Mistakes:

• Swapping the order of arguments in CONTAINS
• Using LEFT or RIGHT instead of CONTAINS
• Passing characters as numbers

3. What is the result of RIGHT('Analytics', 4) in Tableau?

medium

A. 'tics'

B. 'Anal'

C. 'ytic'

D. 'naly'

Solution

1. Step 1: Understand RIGHT function

   RIGHT extracts characters from the end of a string. Here, it extracts 4 characters from 'Analytics'.

2. Step 2: Extract last 4 characters

   The last 4 characters of 'Analytics' are 'tics'.

3. Final Answer:

   'tics' -> Option A

4. Quick Check:

   RIGHT('Analytics', 4) = 'tics' [OK]

Hint: RIGHT gets characters from the end of text [OK]

Common Mistakes:

• Extracting characters from the start instead of end
• Counting wrong number of characters
• Confusing with LEFT function

4. You wrote the formula CONTAINS('Business', Business) in Tableau but it gives an error. What is the problem?

medium

A. The first argument should be a number

B. CONTAINS cannot be used with text

C. LEFT function should be used instead

D. Missing quotes around 'Business' in second argument

Solution

1. Step 1: Check CONTAINS argument types

   CONTAINS requires both arguments to be text strings or fields. Here, second argument is missing quotes, so Tableau treats it as a field name.

2. Step 2: Fix by adding quotes

   Adding quotes around 'Business' in second argument makes it a string literal, fixing the error.

3. Final Answer:

   Missing quotes around 'Business' in second argument -> Option D

4. Quick Check:

   CONTAINS('Business', 'Business') works [OK]

Hint: Always quote text strings inside CONTAINS [OK]

Common Mistakes:

• Using unquoted text instead of string literals
• Confusing CONTAINS with LEFT or RIGHT
• Passing numbers instead of text

5. You want to create a calculated field in Tableau that returns TRUE if the first 2 letters of a product code are 'AB' and the code contains '123'. Which formula is correct?

hard

A. CONTAINS([Product Code], 'AB') AND LEFT([Product Code], 3) = '123'

B. RIGHT([Product Code], 2) = 'AB' OR CONTAINS('123', [Product Code])

C. LEFT([Product Code], 2) = 'AB' AND CONTAINS([Product Code], '123')

D. LEFT([Product Code], 2) = 'AB' AND CONTAINS('123', [Product Code])

Solution

1. Step 1: Check LEFT function usage

   LEFT([Product Code], 2) extracts first 2 letters. We compare it to 'AB' to check the start.

2. Step 2: Check CONTAINS usage

   CONTAINS([Product Code], '123') checks if '123' is anywhere in the code. The order is correct: main text first, substring second.

3. Step 3: Combine conditions with AND

   Both conditions must be true, so use AND.

4. Final Answer:

   LEFT([Product Code], 2) = 'AB' AND CONTAINS([Product Code], '123') -> Option C

5. Quick Check:

   Correct syntax and logic = LEFT([Product Code], 2) = 'AB' AND CONTAINS([Product Code], '123') [OK]

Hint: Use LEFT for start, CONTAINS for anywhere, combine with AND [OK]

Common Mistakes:

• Swapping LEFT and RIGHT functions
• Reversing arguments in CONTAINS
• Using OR instead of AND