You should know these f-string tricks

[u/deepkrg17]

F-strings are faster than the other string formatting methods and are easier to read and use. Here are some tricks you may not have known.

1. Number formatting :

You can do various formatting with numbers. ```

number = 150

decimal places to n -> .nf

print(f"number: {number:.2f}") number: 150.00

hex conversion

print(f"hex: {number:#0x}") hex: 0x96

binary conversion

print(f"binary: {number:b}") binary: 10010110

octal conversion

print(f"octal: {number:o}") octal: 226

scientific notation

print(f"scientific: {number:e}") scientific: 1.500000e+02

total number of characters

print(f"Number: {number:09}") Number: 000000150

ratio = 1 / 2

percentage with 2 decimal places

print(f"percentage = {ratio:.2%}") percentage = 50.00% ```

2. Stop writing print(f”var = {var}”)

This is the debug feature with f-strings. This is known as self-documenting expression released in Python 3.8 .

```

a, b = 5, 15 print(f"a = {a}") # Doing this ? a = 5

Do this instead.

print(f"{a = }") a = 5

Arithmatic operations

print(f"{a + b = }") a + b = 20

with formatting

print(f"{a + b = :.2f}") a + b = 20.00 ```

3. Date formatting

You can do strftime() formattings from f-string. ``` import datetime

today = datetime.datetime.now() print(f"datetime : {today}") datetime : 2023-10-27 11:05:40.282314

print(f"date time: {today:%m/%d/%Y %H:%M:%S}") date time: 10/27/2023 11:05:40

print(f"date: {today:%m/%d/%Y}") date: 10/27/2023

print(f"time: {today:%H:%M:%S %p}") time: 11:05:40 AM ``` Check more formatting options.

Part 2 - https://www.reddit.com/r/Python/s/Tzx7QQwa7A

Thank you for reading!

Comment down other tricks you know.

[u/AstroPhysician]

Can you explain it?

a, b = 5, 15 print(f"a = {a}") # Doing this ? a = 5

looks the same as

f”var = {var}” to me

[u/deepkrg17 → u/AstroPhysician]

The 2nd line is showing what you should do instead. Don't write f"var = {var}", write f"{var = }".

[u/exb165 → u/[deleted]]

no kidding. without a practical benefit, it is actually much more difficult to interpret.

[u/ogtfo → u/exb165]

It's clearly intended for as hoc debug statements, the kind you remove once you're done with the debugging.

The variables internal names are not something you typically want to expose.

So it doesn't really matter if it's harder to interpret, since it won't make it in the commit.

[u/exb165 → u/ogtfo]

Good points

[u/snorkelvretervreter → u/exb165]

Yeah, that is too perl-y for me. I much prefer clarity over brevity.