8 More Things I Never Knew About Python Until Recently

# 7) Password prompting in Python while hiding whatever our user types

1) We Can Programatically Open Our Browser Using Python

import webbrowser

webbrowser.open_new("https://medium.com")

Note — the webbrowser module is pre-installed, so we don’t have to install it using Pip. Running the above code opens a new tab of medium.com on whichever browser we are using.

2) Easier Way To Debug Using F-Strings

name = "rocky"
age = 4
breed = "german shepherd"

print(f"{name=} {age=} {breed=}")

The output:

name='rocky' age=4 breed='german shepherd'

Which allows us to type less stuff when we debug.

3) Python Has A Built-In Median Function

# And other statistics-related functions

from statistics import median

lis = [1, 5, 3, 4, 2]

print(median(lis))   # 3

The statistics module is a built-in module that we don’t have to install using Pip, and it contains many other statistics-related functions. I did not know about this, and have been using np.median from Numpy all this while!

4) Built-in Fractions In Python

from fractions import Fraction

x = Fraction(1/2)

print(x**2)   # 1/4

Python has built-in fractions that don’t return float numbers in the fractions module. Once again, this is part of the Python Standard Library, and we don’t need to install it using Pip.

5) locals() and globals()

The built-in globals() function allows us to check what global variables we have, and the built-in locals() function allows us to check what local variables we have in the scope of a function.

x = 1
y = 2

def test():
    z = 3
    print(globals())
    print(locals())

test()

The output:

# globals()
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x108a30dc0>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, '__file__': '/Users/lzl/Documents/repos/test/aa.py', '__cached__': None, 'x': 1, 'y': 2, 'test': <function test at 0x10896beb0>}

# locals()
{'z': 3}

We can even assign global/local variables using globals() and locals(). But I recommend you not to due to the potential side effects.

x = 1

def test():
    globals()["x"] = 5

test()
print(x)   # 5

6) The __debug__ Variable

# Probably the only variable we cannot reassign in Python

The __debug__ variable is a boolean value that is usually True when we run our Python script normally. However, if we run our Python script using the -O flag, __debug__ is set to False.

python3 -O yourscript.py

When __debug__ is False, assert statements are ignored.

assert 1==2

^ If we run the above code normally, we get an AssertionError. However, if we run it with the -O flag, __debug__ is set to False, and the assert statement is ignored.

7) Password prompting in Python while hiding whatever our user types

Notice how many command line interfaces eg. git, docker etc do not print your password when you type it? We can achieve the same effect in Python using the built-in getpass module.

from getpass import getpass

password = getpass()

print(password)

^ Here, when prompted for a password, I typed "abcdefg" into the command line. What I type isn’t printed due to getpass, but is stored in the variable password.

8) Turtle

import turtle

screen = turtle.getscreen()
x = turtle.Turtle()

for i in range(1000):
    x.forward(200)
    x.right(115)

Copy this code and run it on your computer. And wait for magic to happen.

Conclusion

Hope you learnt at least ONE new thing about Python after reading this!

Some Final words

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