Python SyntaxError (invalid syntax)

This Python page is about SyntaxError and how programs with invalid syntax cause this error.
SyntaxError. A Python program must have correct syntax. If it does not, a SyntaxError will occur. The program will not be executed. This error, unlike other errors, does not terminate a running program—an "except" statement cannot handle it.
Example. Here I wrote an important program to loop over a list of cat names. But in the for-statement, I omitted the trailing colon. This results in a SyntaxError, which politely points out the missing colon character.

So: To fix the program, we can add a colon to the indicated location. Until then, the program cannot be executed.

Python program that causes SyntaxError cats = ["Fluffy", "Mildred", "Joe"] for cat in cats print(cat) Output File "C:\programs\file.py", line 5 for cat in cats ^ SyntaxError: invalid syntax
Example 2. In this version of the program, no error occurs. I included this for completeness. The names of the three cats are correctly looped over and displayed to the console with the print statement.WhilePrint
Python program that causes no error cats = ["Fluffy", "Mildred", "Joe"] for cat in cats: print(cat) Output Fluffy Mildred Joe
Try. A SyntaxError is not like other errors in Python. It cannot be handled in a try and except construct. There is no way to force a program with invalid syntax to run correctly (other than fixing it).

Note: In an experiment, I found the SyntaxError penetrates all "except" statements. This error occurs before the program is run.

Summary. This error is a form of "compile-time" error: one that stops a program from ever being run. These errors may be annoying, but they also prevent grossly incorrect programs from ever causing trouble in the world.
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