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Mike Driscoll

@driscollis

Feb 12

It's the weekend, so now's a great time to talk about #Python and SQLite! 🐍

Python works with SQLite, a file-based database, right out of the box via its built-in `sqlite3` library.

Here's how you could connect to a SQLite database with Python:

When you use the `sqlite3` module in Python, you will be using regular SQL to work with it.

So to create a table, you would do something like this:

The following code shows how to insert one row of data into a table as well as how to insert multiple rows using SQL and sqlite3 in Python 🐍🔥

Read 8 tweets

Mike Driscoll

@driscollis

Feb 10

#Python includes a `locals()` function that is built-in too.

It will update and return a dictionary representing the current local symbol table.

#python_builtins_by_driscollis

🧵🐍👇

According to the #Python docs, "free variables are returned by locals() when it is called in function blocks, but not in class blocks."

Also note that at the module level, locals() and globals() are the same dictionary.

Here are a couple of examples of using Python's `locals()` function:

Read 5 tweets

Mike Driscoll

@driscollis

Jan 19

One of #Python's most controversial built-in functions is `eval()`. The main reason it is controversial is that it can be used to execute arbitrary code.

#python_builtins_by_driscollis

🧵🐍👇

The arguments for `eval()` are a string and optional globals and locals. If provided, globals must be a dictionary. If provided, locals can be any mapping object.

Here is an example:

You can use `eval()` to evaluate/execute the arbitrary code objects that you get when you run Python's `compile()` function.

The `eval()` built-in is closely related to the `exec()` built-in. `exec()` will take a code block while `eval()` only takes a single expression

Read 4 tweets

Mike Driscoll

@driscollis

Jan 9

Let's talk a little about accessing #Python dictionaries!

Most beginners will access a dictionary like this:

🧵🐍👇

What happens if you try to access a key that doesn't exist in a #Python dictionary?

You'll get a KeyError!

There are several different ways to handle a KeyError. 🐍⚠️

You could wrap it in a `try/except`. Another approach is to use the `get()` dictionary method, like this:

Read 6 tweets

Mike Driscoll

@driscollis

Jan 7

Python includes a built-in callable named `bytearray()`.

The bytearray class is a mutable sequence of integers in the range 0 <= x < 256. They return a new array of bytes

#python_builtins_by_driscollis

🧵🐍👇

A bytearray in #Python takes the following optional arguments:

🐍 source[optional]: Initializes the array of bytes
🐍 encoding[optional]: Encoding of the string
🐍 errors[optional]: Takes action when encoding fails

It is often useful to see an unfamiliar concept in action. Here are two examples of creating a bytearray using different encodings and printing them out

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Mike Driscoll

@driscollis

Jan 7

Starting in Python 3.7, the `breakpoint()` built-in function was added

It is defined in PEP 553 and simplifies adding a breakpoint to your code

#python_builtins_by_driscollis

🧵🐍👇

You can read about the `breakpoint()` function for Python here:

python.org/dev/peps/pep-0…

Here is some sample code showing how to use the `breakpoint()` function in your Python code

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