How to use float filter to show just two digits after decimal point?

Question

I am using Flask/Jinja2 template to show a number using |float filter.

Here is my code

{% set proc_err = nb_err|length / sum * 100 %} ({{proc_err|float}}%) 

Output is a bit awkward:

17/189 (8.99470899471%) 

I am looking for a way to make the places after dot limited to a number e.g. 2.

Desired output:

17/189 (8.99%) 

Answer 1

It turns to be quite simple:

My code:

{% set proc_err = nb_err|length / sum * 100 %} ({{proc_err|float}}%) 

Can be changed a bit with:

{% set proc_err = nb_err|length / sum * 100 %} ({{'%0.2f' % proc_err|float}}%) 

or using format:

({{'%0.2f'| format(proc_err|float)}}%) 

Reference can be found here on jinja2 github issue 70

Answer 2

You can use round to format a float to a given precision.

Extracted from the docs:

round(value, precision=0, method='common')

Round the number to a given precision. The first parameter specifies the precision (default is 0), the second the rounding method:

• common rounds either up or down
• ceil always rounds up
• floor always rounds down

If you don’t specify a method common is used.

{{ 42.55|round }}     -> 43.0 {{ 42.55|round(1, 'floor') }}     -> 42.5 

Note that even if rounded to 0 precision, a float is returned. If you need a real integer, pipe it through int:

{{ 42.55|round|int }}     -> 43