Resolving the Type Mismatch Error in VBA: How to Exclude Duplicates from an Array

Learn how to troubleshoot the prevalent `Type Mismatch` error in VBA code when working with collections and arrays, particularly when comparing data from different Excel sheets.
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Understanding the VBA Type Mismatch Error

When working with VBA in Excel, encountering a Type Mismatch error can be particularly frustrating. This error often arises when adding values to a collection, especially when the values being added do not match the expected data type.

In this guide, we will walk through a specific example where a user attempted to extract names from one array but was halted by a Type Mismatch error when trying to add values to a collection from a second array. We will explore what causes this error and how to fix it, while ensuring that our solution maintains efficiency.

The Problem

The user faced the following scenario:

They had two arrays containing names extracted from different ranges in Excel sheets.

The goal was to create a third array that would only include names present in the first array but not in the second.

The error occurred on this line of code:

[[See Video to Reveal this Text or Code Snippet]]

The Type Mismatch error was triggered when they attempted to execute this line in a loop, which should have otherwise been a straightforward process.

Potential Causes of the Issue

Data Type Inconsistencies: If the values in Array1 or Array2 include types that cannot be added to the collection (like an error value or an empty value), it would trigger a Type Mismatch.

Different Sheets: Since the arrays were derived from different Excel sheets, it could lead to comparisons that didn't function as expected.

Conflicting Data: Similar names formatted differently may not match correctly when checking for duplicates.

The Solution

We'll optimize the code while addressing the error and ensuring proper functionality. The revised code below demonstrates an improved approach to solve the problem by reformulating how we check for names:

Revised VBA Code:

[[See Video to Reveal this Text or Code Snippet]]

Breakdown of the Solution

Check for Empty Values: Before adding values to the collection, ensure that they are not empty using If Len(v) > 0 Then.

Use Application.Match: This built-in function provides a simple way to check if a value exists in the given range. By leveraging this function, we ensure that we are efficiently looking up values.

Collection Handling: The structure of adding items to a collection is simplified to avoid direct comparisons that could lead to errors.

Resizing New Array: Finally, the new array (arrOut) is populated with valid entries from the collection, maintaining performance and simplicity.

Conclusion

Encountering a Type Mismatch error in VBA can disrupt your workflow. However, by understanding the underlying issues related to data types and utilizing efficient collection methods, you can resolve these errors effectively. The provided solution ensures that you can filter and create an array as intended without encountering mismatched types. If you continue to face issues, always double-check the types of the data your arrays are handling. Happy coding!