You Probably Don't Know Python - Part 2

sample-1.py

# Without Walrus Operator
n = len("Hello, World")
if n > 10:
    print(f"WoW, {n} is Tooooo Large!")

# With Walrus Operator
if (n := len("Hello, World")) > 10:
    print(f"WoW, {n} is Tooooo Large!")

sample-2.py

# Without Walrus Operator
[normalize('NFC', name).title() for name in names
 if normalize('NFC', name) in allowed_names]

# With Walrus Operator
[clean_name.title() for name in names
 if (clean_name := normalize('NFC', name)) in allowed_names]

sample-3.py

# Without Walrus Operator
with open('my-binary', 'rb') as myfile:
    while True:
        block = myfile.read(128)
        if block == '':
            break
        do_something(block)


# Without Walrus, But Smarter
from functools import partial

with open('my-binary', 'rb') as myfile:
    for block in iter(partial(myfile.read, 128), b''):
        do_something(block)
            

# With Walrus Operator
with open('my-binary', 'rb') as myfile:
    while (block := myfile.read(128)) != '':
        do_something(block)

sample-4.py

from datetime import datetime

a_float = 0.854623
a_string = "Joe"
today = datetime(year=2020, month=7, day=4)
width = 10
precision = 4
value = 12.3456789

print(f"Hello, {a_string!r}")                      # Hello, 'Joe'

print(f"{a_string} height is {a_float * 100:.0f}") # Joe height is 85

print(f"Download Progress is {a_float:%}")         # Download Progress is 85.462300%

print(f"Today is {today:%B %d, %Y}")               # Today is July 04, 2020

print(f"Result: {value:{width}.{precision}}")      # Result:      12.35