Type mismatch errors occur when you try to connect nodes with incompatible data types. Don’t worry though - they’re easy to understand and fix once you know what to look for! This guide will help you identify these errors and show you exactly how to resolve them.
A type mismatch error occurs when you try to connect nodes that expect different types of data. In Gumloop, data flows between nodes in two main formats:
The basic rule is simple:
However, there’s a special case: You can pass a list into a node that expects text by enabling “Loop Mode”. When Loop Mode is on, the node will process each item in the list one by one.
For example:
A type mismatch typically happens when you try to:
Send a list where a node expects a single text
Example: Trying to send [email1, email2, email3] to a node that expects just one email
Send a single text where a node expects a list
Example: Trying to send one email to a node that expects [email1, email2, email3]
When this happens, you’ll see a red error message warning you about the mismatch. The good news is that these errors are easy to fix using the right nodes, which we’ll cover in this guide.
The Problem: You have a list of items (like multiple research topics from a Google Sheet) that you want to process as a single text input (like merging them and sending as a single message on Slack).
Example:
Error Message: Single Value Expected, List Received
The Solution: Use the Join List Items node to combine all items in the list into a single text string.
Steps:
Common Use Case:
The Problem: You have a single text item (like a writing style guide from a Google Doc) that needs to be used with each item in a list (like multiple blog posts that need the same style guide).
Example:
Error Message: List Expected, Single Value Received
The Solution: Use the Duplicate node to create a list containing multiple copies of your text.
Steps:
Common Use Case:
The Problem: You have a nested list (a list containing other lists) but need a simple, flat list.
Example:
Error Message: List Expected, List of List Received
Check Node Types:
Understanding Loop Mode:
Example: If you have a Google Sheet with a column that you want to send to AI as a whole for context, you’d use a
Join List Items
node to merge the contents of each row from that column instead of enabling loop mode and processing each row in a loop.
Plan Your Data Flow:
Scenario | Problem | Solution Node | How It Works |
---|---|---|---|
List → Text | Need to combine multiple items into one | Join List Items | Concatenates all items in a list into a single text string, using a separator |
Text → List | Need to use one item with many | Duplicate | Creates multiple copies of a single text input to match the size of another list, ensuring compatible data structures |
List of Lists → List | Have nested lists that need flattening | Subflow or Flatten List | Either processes inner lists through a dedicated flow (Subflow) or combines all nested items into a single-level list (Flatten List) |
Still stuck? If you’ve tried these solutions and still can’t resolve your type mismatch error, reach out on forum.gumloop.com and we’ll help!
Type mismatch errors occur when you try to connect nodes with incompatible data types. Don’t worry though - they’re easy to understand and fix once you know what to look for! This guide will help you identify these errors and show you exactly how to resolve them.
A type mismatch error occurs when you try to connect nodes that expect different types of data. In Gumloop, data flows between nodes in two main formats:
The basic rule is simple:
However, there’s a special case: You can pass a list into a node that expects text by enabling “Loop Mode”. When Loop Mode is on, the node will process each item in the list one by one.
For example:
A type mismatch typically happens when you try to:
Send a list where a node expects a single text
Example: Trying to send [email1, email2, email3] to a node that expects just one email
Send a single text where a node expects a list
Example: Trying to send one email to a node that expects [email1, email2, email3]
When this happens, you’ll see a red error message warning you about the mismatch. The good news is that these errors are easy to fix using the right nodes, which we’ll cover in this guide.
The Problem: You have a list of items (like multiple research topics from a Google Sheet) that you want to process as a single text input (like merging them and sending as a single message on Slack).
Example:
Error Message: Single Value Expected, List Received
The Solution: Use the Join List Items node to combine all items in the list into a single text string.
Steps:
Common Use Case:
The Problem: You have a single text item (like a writing style guide from a Google Doc) that needs to be used with each item in a list (like multiple blog posts that need the same style guide).
Example:
Error Message: List Expected, Single Value Received
The Solution: Use the Duplicate node to create a list containing multiple copies of your text.
Steps:
Common Use Case:
The Problem: You have a nested list (a list containing other lists) but need a simple, flat list.
Example:
Error Message: List Expected, List of List Received
Check Node Types:
Understanding Loop Mode:
Example: If you have a Google Sheet with a column that you want to send to AI as a whole for context, you’d use a
Join List Items
node to merge the contents of each row from that column instead of enabling loop mode and processing each row in a loop.
Plan Your Data Flow:
Scenario | Problem | Solution Node | How It Works |
---|---|---|---|
List → Text | Need to combine multiple items into one | Join List Items | Concatenates all items in a list into a single text string, using a separator |
Text → List | Need to use one item with many | Duplicate | Creates multiple copies of a single text input to match the size of another list, ensuring compatible data structures |
List of Lists → List | Have nested lists that need flattening | Subflow or Flatten List | Either processes inner lists through a dedicated flow (Subflow) or combines all nested items into a single-level list (Flatten List) |
Still stuck? If you’ve tried these solutions and still can’t resolve your type mismatch error, reach out on forum.gumloop.com and we’ll help!