Trusted answers to developer questions

Chinweuba Elijah Azubuike

Grokking Modern System Design Interview for Engineers & Managers

Ace your System Design Interview and take your career to the next level. Learn to handle the design of applications like Netflix, Quora, Facebook, Uber, and many more in a 45-min interview. Learn the RESHADED framework for architecting web-scale applications by determining requirements, constraints, and assumptions before diving into a step-by-step design process.

**Predicates** are functions that examine a condition and send a boolean value, which is either true or false. We have predicate functions like the even number. Each predicate function has been discussed in detail in a previous shot. We can search for these shots to learn about the functionality of different predicate functions.

`every`

function?The **every**** function** takes in a predicate function to evaluate a passed parameter passed. In the case when we want to test if a group number is even,* *we may use a predicate function called the **even**** predicate function**.

(every? p2 pn)

Syntax of the every function

Where

is the predicate function and **p2**

are the parameters to be tested.**pn**

The `every`

function receives a predicate function to evaluate the passed parameter, as we will see in an example below.

The `every`

function returns either `true`

or `false`

, depending on if the passed parameter satisfies the predicate function.

(ns clojure.examples.example(:gen-class))(defn func [](println (every? zero? '(2 4 6)))(println (every? even? '(2 4 6))))(func)

Example of the every function

- Line 3: We defined a function called
`func`

.

- Line 4: We use a predicate function,
`zero?`

, alongside the`every`

function to evaluate the passed parameter`2 4 6`

, and then we print out the output. Notice that the output is`false`

because even though the values passed are numbers, these values fail the test by the`zero`

predicate function, as the`zero`

predicate function checks to see if a number is zero.

- Line 5: We use a predicate function,
`even?`

, alongside the`every`

function to evaluate the passed parameter`2 4 6`

, and then we print out the output. Notice that the output is`true`

because the values passed are numbers. These values pass the test by the`even`

predicate function, because the`even`

predicate function checks to see if a number is even.

- Line 6: We call the function named
`func`

.

RELATED TAGS

clojure

every method

predicate

CONTRIBUTOR

Chinweuba Elijah Azubuike

Grokking Modern System Design Interview for Engineers & Managers

Ace your System Design Interview and take your career to the next level. Learn to handle the design of applications like Netflix, Quora, Facebook, Uber, and many more in a 45-min interview. Learn the RESHADED framework for architecting web-scale applications by determining requirements, constraints, and assumptions before diving into a step-by-step design process.

Keep Exploring

Related Courses