Is None

A simple utility block that checks whether a given value is missing (None) and returns a boolean result. Use it to guard logic and prevent errors when a previous block may not provide a value.

📥 Inputs

Generic A value to check. This can be any data type or image output from another block.

📤 Outputs

Boolean True when the input is None, otherwise False.

🕹️ Controls

This block has no user-configurable controls.

✨ Features

• Straightforward presence check for any incoming data.

• Useful to drive conditional flows or to trigger fallback behavior.

• Lightweight and safe to place before blocks that require valid data.

📝 Usage

• Connect the output of any block to the Generic input to test whether that block currently provides a value.

• Use the Boolean output to control logic blocks (for example to gate processing, reset flows, or enable fallback actions).

• Place this block before blocks that would fail or produce unwanted results when fed with missing data.

📊 Evaluation

When evaluated, the block returns a single boolean value indicating whether the provided input is missing. This output can be used immediately in logic operations or to trigger recovery steps.

💡 Tips and Tricks

• Combine with Replace None to automatically supply a fallback value when the input is missing.

• Use with Data Memory to freeze or hold a previously valid value and avoid repeated None propagation.

• Route the result into logic blocks like Not, And, or Or to build complex conditional flows.

• Feed the boolean into Set - Reset or All True when implementing multi-condition controls or latching behaviour.

• Use Debug Input to log or inspect the input before and after the check during setup and troubleshooting.

• When guarding image processing chains, pair with visualization/export blocks such as Show Image or Image Logger so you only pass valid images to viewers or file sinks.

🛠️ Troubleshooting

• If the block always outputs True, verify the upstream block is connected and producing data.

• If behaviour is intermittent, consider holding valid values with Data Memory or logging inputs with Debug Input to see when data is missing.