How to use float filter to show just two digits af

问题:

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%)

回答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

回答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

回答3:

Here is one approach ::

{{ "%.2f"|format(result) }}

Tweak it as you like :)

回答4:

(I'm assuming you use to Ionic v2)

Use this front-end code:

<div *ngIf="device.usage > 0">
   {{ Round(device.usage)}} min  
</div>

and put the following function into the .ts file:

Round(number):number
{
    return parseFloat(Number((number/1000) / 60).toFixed(2)); 
}