Common Python Errors
This post is updated as appropriate, so keep checking back!
Table of Contents
Errors when installing python with homebrew Errors when writing/running python code
Table of Contents
Errors when installing python with homebrew Errors when writing/running python code
Installing Python
Error: Permission denied @ dir_s_mkdir – /usr/local/Frameworks
Check out this article for help: https://github.com/Homebrew/homebrew-core/issues/19286Error: Could not symlink bin/2to3
Check out this article for help: https://stackoverflow.com/questions/13354207/how-to-symlink-python-in-homebrewWriting Python Code
TypeError: Can’t convert …
This means one of a few things:- That you are trying to combine data types that aren’t compatible. You can’t concatenate a string and an integer for example.
- You’re trying to perform some operation on the wrong datatype for that function.
NameError: global name ‘—‘ is not defined
Did you forget to put something in quotes? Remember if you didn’t define something as a variable, list, dictionary, etc. previously, and it’s not a number, it needs to be in quotes!IndentationError: expected an indented block
There are several types of indentation errors. These are pretty self-explanatory. You either forgot an indent or have too many. Remember, python considers indents to be four spaces or a tab, exactly.SyntaxError: invalid syntax
This could mean a lot of things, but basically you aren’t following one of the basic syntax rules of Python. Here are some common examples:- Forgetting the parens around the arguments to print
- Forgetting the colon at the end of the condition in an if statement, or in a for loop
- Trying to use a reserved word as a variable name
- Code like:
if my_variable = 8:(should be == 8 when in an IF statement!)
IndexError: list index out of range
Typically this means you are trying to access an item in a list that doesn’t exist. For example, :
flowers = ["rose", "tulip", "daisy"]
print("Flowers in my garden are:", flowers[1], flowers[2], flowers[3])
There is no flowers[3]! Remember, lists start at 0, so it should have been flowers[0], flowers[1], flowers[2].
KeyError
These seem scary, but they are similar to the NameError, only specific to dictionaries. They are raised when a key is not found in the set of existing keys. Check for spelling and case sensitivity!ValueError
This is most commonly caused by trying to convert a bad string into a number. For example:my_num = int("Word").
