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Let Formula in Google Sheets

Simplify Your Long and Complex Formulas in Google Sheets with LET Function

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Are you struggling with long, unwieldy formulas in Google Sheets that are difficult to read, understand, and maintain?  The `LET` function offers a powerful solution to simplify your complex formulas and boost your productivity. This guide will show you how.

Understanding the Syntax and Structure of LET

The `LET` function allows you to define named variables within a formula. This makes your formulas much more readable and easier to debug. The basic syntax is:

`LET(name1, value1, [name2, value2, …], formula)`

  1. `name1`, `name2`, etc.:  These are the names you assign to your variables. They must be valid identifiers (alphanumeric characters, starting with a letter).
  2. `value1`, `value2`, etc.: These are the values assigned to your variables. They can be numbers, text strings, cell references, or other formulas.
  3. `formula`: This is the final calculation that uses the defined variables.

Simplest Example of LET

You want to calculate a discount based on the total price:

  • If the total price is greater than $100, apply a 10% discount.
  • Otherwise, no discount.
  • LET assigns A1 to the variable price, making the formula easier to read and manage.
  • This is helpful in larger, more complex formulas where you reference the same value multiple times.

Breaking Down Complex Formulas with LET: A Step-by-Step Guide

Let’s illustrate with an example. Imagine this complex formula:

=IF(XLOOKUP(INDIRECT("B"&ROW(B15)-RIGHT(B15,LEN(B15)-SEARCH(".",B15))-2)&" "&B15,'Question bank data'!$G$2:$G,'Question bank data'!$H$2:$H,"not found")="", "", XLOOKUP(INDIRECT("B"&ROW(B15)-RIGHT(B15,LEN(B15)-SEARCH(".",B15))-2)&" "&B15,'Question bank data'!$G$2:$G,'Question bank data'!$H$2:$H,"not found"))

This formula is hard to decipher. Using `LET`, we can break it down:

=LET(lookup_key, INDIRECT("B"&ROW(B16)-RIGHT(B16,LEN(B16)-SEARCH(".",B16))-2)&" "&B16, result, XLOOKUP(lookup_key, 'Question bank data'!$G$2:$G, 'Question bank data'!$H$2:$H, "not found"), IF(result="", "", result))

We’ve defined `lookup_key` and `result`, making the formula significantly clearer.

Step-by-Step Breakdown

1. Identify Repeating Parts: Find sections of your formula that are repeated.

2. Assign Variable Names: Give meaningful names to these repeated parts.

3. Define Variables: Use the `LET` function to assign the names to their corresponding values.

4. Rewrite the Formula: Replace the repeated parts in your original formula with the variable names.

Best Practices for Writing Efficient LET Formulas

  1. Use descriptive variable names.
  2. Break down complex formulas into smaller, manageable parts.
  3. Comment your formulas for clarity.