What does this statement construction mean?: if (null != anim)

Question

From the Unity documentation (https://docs.unity3d.com/ScriptReference/Animator.Play.html), the following code example is given:

 public class Move : MonoBehaviour
 {
     private Animator anim;
 
     void Start()
     {
         anim = GetComponent<Animator>();
     }
 
     void Update()
     {
         if (Input.GetKeyDown(KeyCode.Space))
         {
             if (null != anim)
             {
                 // play Bounce but start at a quarter of the way though
                 anim.Play("Bounce", 0, 0.25f);
             }
         }
     }
 }

I understand when statements like if (x != null) means but

What does it mean when null and the variable positions are swapped as above?
What does it mean to have your animator be null or not null? Is it just checking that an animator exists?
If so, that really a necessary step?

Answer 1

Answer by zereda-games · Feb 19, 2019 at 05:50 PM

Read post above first

null means: gone, missing, or emptylist/array,
!: means Not<- , aka, opposite, isn't t$$anonymous$$s.
anim is referencing an Animator class
anim = GetComponent(); Literally was just reading and corrected on the post i was on previous of yours. GameObject.FindWithTag("StringValue"); seems to be most popular, FindObjectOfType""(); works but is very expensive on performance to do often as it looks through the Whole scene for the first object of that type that it can find. were FindWithTag, only looks at objects with tags and only looks for a specific string if it is in the Tag's List..

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Siggytron · Feb 19, 2019 at 06:18 PM 0

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So do you know if there's a difference in the if statement between saying:

null != anim

or

anim != null

Are these two interchangeable?

Bunny83 Siggytron · Feb 19, 2019 at 06:28 PM 2

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Those are interchangeable and any sane person would write

 if (anim != null)

More specifically the un-equal operator != simply compares two values for inequality and returns a boolean (true or false).

Note that != is one operator and has nothing to do with the unary ! not operator. Though it serves a similar purpose.

zereda-games Bunny83 · Feb 19, 2019 at 06:33 PM 0

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Thanks, i hate being wrong.

What does this statement construction mean?: if (null != anim)

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