Learning Python

The observation of Python's authors is that programs are more often read than written. Therefore, they have adopted a specific style guide. If you're writing Pythhon code, you should adher to it, because

• others that see your programs will nag about it
• if you're used to the style, it will be easier to read programs by others

There are some strange choices in the PEP8 standard. They make programs needlessly long and, for a beginning Python programmer, harder to read. They are also inconsistent in a number of ways.

This chapter does not explain the complete PEP8. I threw my code through an on-line PEP8 checker and these are the errors that I found in my code and my observation of them.

Equal signs must have spaces around them, for example:

a = 1+1

Unless, the equal sign is used for an assignment of named arguments. Other operators should not have spaces around them.

A comma should have a space after it.

a=function(arg1, arg2)

And parentheses do not get spaces.

The colon that is used for block starts should also not get a space:

def function(arg):

And comments start with '# ' (hash-space).

Maximum line length is 80. Why? Because the IBM punch-card format, introduced in 1928 had 80 columns.

One of the horrors of Python is it's attitude towards indents. Indents are used to mark blocks. Indents are 4 spaces. Not a tab, four spaces. Together with the 80-column limit, this also means a maximum for nesting blocks (19), but if you hit that limit, you should restructure your code anyway.