These Python statements are commonly used when handling uploaded files, especially in applications built with Streamlit.

1. Check whether a file was uploaded 

if uploaded_file is not None:
  • if checks a condition.
  • uploaded_file is a variable that holds the uploaded file.
  • is not None checks that the variable contains a value rather than None.

Purpose: Run code only when a file has been uploaded.

2. Use try to run code safely 

try:
  • try contains code that Python attempts to execute.
  • If the code succeeds, Python continues normally.
  • If an exception occurs, Python can move to an except block.

Purpose: Handle operations that might fail, such as reading or processing a file.

3. Use except Exception to handle errors 

except Exception:
  • except = handles an error.
  • Exception = specifies which category of errors to catch.

Purpose: Handle errors that occur during execution.

4. Combine all three 

 if uploaded_file is not None: try: # your code goes here  except Exception: # Error handling goes here

This mini-guide was originally published on PDF Python Hub, where you can find more in-depth Python resources for working with PDFs.