Mastering Flask Web Development - Second Edition

The round filter

The round filter rounds off a float to the specified precision, as follows:

{{ 3.141592653589793238462 | round(1) }} 
3.1 

You can also specify how you want the number to be rounded off, as shown in the following code:

{{ 4.7 | round(1, "common") }} 
5 
{{ 4.2 | round(1, "common") }} 
4 
{{ 4.7 | round(1, "floor") }} 
4 
{{ 4.2 | round(1, "ceil") }} 
5 

The common option rounds such figures in the same way that a person would: Any number at or above 0.5 is rounded up, and any number lower than 0.5 is rounded down. The floor option always rounds the number down and the ceil option always rounds up, regardless of the decimal value.