Specifying width of concatenated variables in a f-string

Question

I'm using the loguru package for logging in my python project.

I'm looking to override the default format so I can specify a fixed with for the module / function / line number string.

Here's the default format ...

'<green>{time:YYYY-MM-DD HH:mm:ss.SSS}</green> | <level>{level: <8}</level> | <cyan>{name}</cyan>:<cyan>{function}</cyan>:<cyan>{line}</cyan> - <level>{message}</level>'

The output is something like this ...

2020-12-28 14:36:27.510 | INFO     | package1.module1:function:132 - Listing Users...
2020-12-28 14:36:27.601 | ERROR    | package10.module10:function10:1000 - The provided token has expired

I want to add a static width/padding to the package/module/function so the output looks like ...

2020-12-28 14:36:27.510 | INFO     | package1.module1:function:132      - Listing Users...
2020-12-28 14:36:27.601 | ERROR    | package10.module10:function10:1000 - The provided token has expired

The problem is the full path with function line number is constructed from 3 variables ...

<cyan>{name}</cyan>:<cyan>{function}</cyan>:<cyan>{line}</cyan>

Is there any way I can specify a width for the combination of the strings? Something like ...

<cyan>{name + ":" + function + ":" + line : 45}</cyan>

Appreciate the help!

The {level: <8} part does this; you can do {name + ":" + function + ":" + line: <45} just the same way. — kaya3
– kaya3, Commented Dec 28, 2020 at 23:44

Georgina Skibinski · Accepted Answer · 2020-12-28 23:19:09Z

1

You can always limit string length, just like you would do with any sequence:

# 150 chars string:
x = "abc" * 50

# 30 chars string:
y = "xyz" * 10

# predefined display limit:
n = 45

spaces = " " * n
print(f"{(x+spaces)[:n]} end line")
print(f"{(y+spaces)[:n]} end line")
print(f"{(y+x+spaces)[:n]} end line")

Outputs:

abcabcabcabcabcabcabcabcabcabcabcabcabcabcabc end line
xyzxyzxyzxyzxyzxyzxyzxyzxyzxyz                end line
xyzxyzxyzxyzxyzxyzxyzxyzxyzxyzabcabcabcabcabc end line

edited Dec 28, 2020 at 23:19

answered Dec 28, 2020 at 22:49

Georgina Skibinski

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2 Comments

Tyler Weiss Over a year ago

Thank you for your answer, sadly that doesn't align the string to the right of 'x' and 'y'. The desired output would have "end line" aligned

Georgina Skibinski Over a year ago

@TylerWeiss - have a look now - this should do the trick (you may want to pack the whole thing in a function for code clarity)

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