Seven Tips To Clean Code With Python

Unpacking variables are probably most used for functions that return multiple variables, such as in the example below.

But it is also useful for data types that contain multiple items. The only important notion here is that, if not otherwise defined, variable unpacking results in tuples .

The _ operator is an unnamed variable , essentially a variable that you’re not interested in and won’t be doing anything with, for instance in the following case:

Dictionaries are great data-types for storing values with an attribute field known as the key , in so-called key-value pairs . When extracting key-value pairs from dictionaries, avoid running into KeyError exceptions with the .get method instead of the more traditional [key] method. The .get method provides a default value if the key is not present.

In line 6-10 our program stops running because of the KeyError exception, but in line 11-14 our program continues, using the default 'undefined' string that is set in line 12 as the second argument of the .get method.

When you have the possibility of assigning a default value for accessing key-value pairs in a dictionary, always try to use the .get method to avoid your program from stopping prematurely, especially when in production.

I love the zip function and it has saved me countless (nested) loops. I use it mostly for iterating over two data types at the same time, where I need the indexes to be equal.

You can do this with any data type or generator. For instance, you could create dictionaries without looping over the separate lists, as such:

Later on, we’ll introduce the *args operator, which in combination with the zip function is very powerful!

List, tuple, and dictionary comprehensions are ways to code more efficiently: do the same in fewer lines of code.

Both lines 2-4 and lines 13-15 are compressed in single-line expressions in line 6 and line 17 . This saves up unnecessary loops and creates a cleaner codebase.

the * prefix operator was added to the multiple assignment syntax, allowing us to unpack the remaining items in an iterable.

The ** operator does something similar, but with keyword arguments. The ** operator allows us to take a dictionary of key-value pairs and unpack it into keyword arguments in a function call.