count()

Info

New in Atfinity 17.

Description

count() returns how many elements of a list satisfy a condition.

It is not the method version of COUNT, which takes no condition and returns a length. The two agree where the condition holds for every element, as in list.count(x => true). Reach for count() when you want a subset counted, and COUNT when you want a length. count() only accepts a list, while COUNT also measures a dictionary or a string.

list.count(x => condition) is also shorter than COUNT(list.filter(x => condition)), and it does not build the intermediate list.

Syntax

list.count(element => condition)

Returns: a number, or unknown if the list itself is unknown.

Example

[1, 2, 3, 4, 5].count(number => number > 2)

This returns 3, for the elements 3, 4 and 5.

p is Person
p.countries_lived_in.count(country => country != 'ch') > 2

This is true if the person has lived in more than two countries outside Switzerland.

Empty lists

[].count(number => number > 0) evaluates to 0.