Unknown format code 'g' for object of type 'str'

Question

I am trying to implement a simple function of float numbers and I got this error: Unknown format code 'g' for object of type 'str. What is the cause of this and how do I resolve this.

from django import template
register = template.Library()
@register.filter
def human_format(num):
    num = float('{:.3g}'.format(num))
    magnitude = 0
    while abs(num) >= 1000:
        magnitude += 1
        num /= 1000.0
    return '{}{}'.format('{:f}'.format(num).rstrip('0').rstrip('.'), ['', 'K', 'M', 'B', 'T'][magnitude])

Answer 1

You're passing in a string, not a number, and trying to use number formatting codes on it.

However, are you maybe looking for the built-in filesizeformat ?