# What is if direction: ?

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I am currently playing around with godot 4 and came across this built in CharacterBody3d script template that im trying to understand:

``````extends CharacterBody3D

const SPEED = 5.0
const JUMP_VELOCITY = 4.5

# Get the gravity from the project settings to be synced with RigidBody nodes.
var gravity = ProjectSettings.get_setting("physics/3d/default_gravity")

func _physics_process(delta):
# Add the gravity.
if not is_on_floor():
velocity.y -= gravity * delta

# Handle Jump.
if Input.is_action_just_pressed("ui_accept") and is_on_floor():
velocity.y = JUMP_VELOCITY

# Get the input direction and handle the movement/deceleration.
# As good practice, you should replace UI actions with custom gameplay actions.
var input_dir = Input.get_vector("ui_left", "ui_right", "ui_up", "ui_down")
var direction = (transform.basis * Vector3(input_dir.x, 0, input_dir.y)).normalized()
if direction:
velocity.x = direction.x * SPEED
velocity.z = direction.z * SPEED
else:
velocity.x = move_toward(velocity.x, 0, SPEED)
velocity.z = move_toward(velocity.z, 0, SPEED)

move_and_slide()
``````

The problem: I am not familiar with the expression `if direction:` what kind of if statement is that and what does it mean/do? Where can I maybe read up on that?
Thanks for reading and have a great day

An `if` statement always analyzes a `boolean` value (so, `true` or `false`).
In the case of the above code, `direction` is a `Vector2`. However, if you look at the `Vector2` docs, you’ll see the following statement:
So, `if direction:` will resolve to `true` in any case where the `direction` vector IS NOT `(0,0)`. It will resolve to `false` in any case where the `direction` vector IS `(0,0)`.