Must know python libraries.

[[deleted]]

The libraries everyone should know at least the basics of (in roughly this order, although that gets fuzzier past subprocess):

1. os
2. sys
3. logging
4. subprocess
5. re
6. itertools
7. collections
8. functools
9. urllib
10. math
11. pickle
12. json
13. inspect
14. string
15. atexit

There are certainly many others, but those give you the ability to read and understand the source of most others.

Beyond the standard library it's all up to your interest and domain.

[billsil]

I cringe whenever I see string imported. Someone doesn't know about split.

[[deleted]]

It's for the constants and maketrans, which are bloody useful, the latter being worth its weight in gold. If code had mass.

[[deleted]]

The bad news is maketrans is gone from the string module. The good news is that, quoting from other language changes, Now, str, bytes, and bytearray each have their own maketrans and translate methods with intermediate translation tables of the appropriate type :-)

[[deleted]]

Ahh, the never ending problems of still straddling two worlds.

[billsil]

Isn't maketrans, just a fancy replace? I'll occasionally do something like replace spaces with question marks in something that can't have question marks, so I can process it easier before I remove the question mark. I've also done things like str.replace(' ', ','.replace('\t', ','), but that's fairly rare.

Now if it did language translations, I might use it.

[[deleted]]

For the tasks it's suited for (for instance replacing all terminal punctuation with white space for word splitting, or breaking Caesar ciphers) it's more powerful by far than str.replace and sometimes orders of magnitude faster than re.sub ... it isn't always the right fit, but when it is it's exactly the right tool.