6:50 Magic happening :D. Love when people explain by simply showing how it works, how we do without, and it's much better with. This way you not only understand quicker, but you actually want to use the feature. Excellent video.
@@bobsagget823 I had a hard time understanding it, but I eventually did. He teaches really fast at times, so the more experience you have, the better. But yeah if I were a beginner this would fly far above my head.
Would have been better an example with an event system. For example, when you click a button on UI, you turn all gameobjects to a random color which are subsribed to the event.
For those who are familiar with C, creating a delegate type is the same as creating a typedef for a function pointer. When declaring a delegate, you essentially declare a pointer of that type and assign the function address to it. When invoking a delegate, you indirectly call the function using the pointer. This of course lets you create arrays of delegates making for fast decoding and program flow. You can also have delegates "pointing" to array of delegates making for even more complex decoding.
Hello, I hope you enjoy this mini-series on delegates and events. The second part should be out in a day or two. If you'd like to translate this video, you can do so here: ruclips.net/user/timedtext_video?ref=share&v=G5R4C8BLEOc
Dude, its awesome. I wish I saw this video like few years ago, when I was trying to figure out what the hell it is, all those delegates and lamba expressions :D This video is extremely helpful and easy to understand (imo)
I already learned about those before... But I never actually used them so now at least I will have reference to this whenever I forget something about events, as this is my favourite Unity tutorial channel so far. EDIT: that scoring example was literally best I've ever seen.
I'm still trying to wrap my head around delegates, but I think you've explained them enough for me to try on my own. Thanks again for a wonderful tutorial, Sebastian!!!
The only good video about delegates I found on YT. Everyone else is too busy gibbering the way they understood this concept instead of actually explaining it with clear examples. Good job.
Very down to earth explanation, wish I had seen something like this back in my freshman days. Delegates are a way to parameterize behaviour instead of just values. The way you used it here is perfect example of a functor in real life. C# was a pioneer in implementing these kind of patterns in the language by avoiding a plain old pointer while at the same time actually using one behind the scenes
I have to say. I probably watched 10 or 15 tutorials about delegates and events in c#. This is by far the most effective and clear one. I think that most the coding RUclipsrs don't understand that when we want to learn something new, especially in programming where are so many layers of context, we want to learn in the simple way possible. And what I see most of the time, is the content creator explaining the thing that we want to learn attached to 20/30 other things that are not needed to explain this new thing that we want to learn. First, we ONLY want to learn the new tool, ONLY after that, we can try to apply that new tool to new contexts...So, Thank you for making a good example of what a tutorial must be. Congrats
Thank you very much, I've been programming for almost 3 years now but I never understood delegates. You explained it so clear that finally i learned what delegates are :D
THANK GOD. Was tempted and decided ya know what...the 50 ish minutes he saved me by explaining clearly in 7 minutes instead of an hour with no HEY! WHAT"S UP hyper stuff is worth $5 right there. One time patreon x => x+5
Your videos are extremely professional and clean. The only problem I have is that you are so concise about what you say, that if I blink for a second a miss an important bit of information. Maybe you could take it just a tad slower. My brain would be very thankful. Great channel, already subscribed!
Thank you so much for this video! I never thought about using delegates like that to be honest, i used to just use them in the most basic way to call multiple functions at once, always simply thought of them as event broadcasters. This combined with the lambda expression is going to make some of my code a lot cleaner and less boiler platey, thanks again! :3
Huh! This a very interesting different way to approach this,you are essentially doing Parameter injection on the function. Giving it the implementation of scoreCalculator you really want when calling it.
Thank you Sebastian! Another excellent tutorial. Looking forward to the part two. And really looking forward to a bigger more in depth tutorial on lambda expressions!
This is the third time I watched the video and I still couldn't follow, I'll watch several more times but I think I should read more document about it before pushing this thing into my head. I just have to learn this because it's needed for my game, it make life easier this way too.
It's pretty cool, Lambda expressions are useful ,but variable initialization should be considered when passing functions because not only do you have to worry what's being put on the stack ,but the reinitialized variables can cause latency issues unless dealt with properly. Of course the instance you showed was perfectly fine because that isn't repeating unnecessary code . Good Job Sebastian!! I have high hopes for this mini-series!!
I'm always a bit confused about the differences between Lambda expressions, delegates and events (the things of the type "Action") But still I use Events for my Attack class. Each Attack has an impact-, hit- and activation-Event that is called within Invoke() of the Attack class. When the attack impacts on anything, hits a mortal-target or is activated it publishes the corresponding event with parameters like impactPoint, caster, hitObject etc... . The gain in this is that when i define an attack, i can put whatever function i like into those events or nothing at all. Therefore my utility-attacks use the same class and therefore Invoke as my spell-attacks, the only difference is that when i create the utility-attack i supply an activation effect only (e.g. instantiate some arbitrary game object like a lava patch) while on a normal attack i might define only a hit or impact effect. Without that i would have to create a new function for every single effect my spells might exert. I would have to have a specific function that creates a lava-patch within the Attack class but now i just write "spellLavaPatch.impactEffect (dir, caster, pos) => { CreateSpellObjectbyPrefab(lavaPatch, pos); }" when i define the attack and the creation is neatly included when i call "spellLavaPatch.Invoke(dir, caster);" anywhere At least that's what i do as of now, for me it is the first time utilizing those things.
Delegates is implemention of Delphi 'function of object' (well, it's Anders Hejlsberg after all...). It's kinda logical as using of pointers was declared 'unsafe' but programmers still need to get an access to methods.
Thanks for sharing, had no idea you could do something like this. Might take a while to get my head around before I start using it naturally in practice but it seems helpful :) Also you might want to name this episode Delegates, then the next episode Events. Like having it as 2 separate episodes rather than a short series? Just an idea :) Cheers.
Hi, glad you found it helpful! I chose to make this a 2-part series because it makes a lot of sense to learn about delegates and events at the same time (given that events are simply delegates with a few restrictions). I've edited the title to clarify that this episode only covers delegates though. Cheers :)
Events are great, but in some cases standard method calling can be more suitable - especially if you're making a strictly turnbased tactical game with an AI Sequence for example. I personally found that being able to see the methods being explicitly called within a complex algorithm (spread over several scripts) made it far, far easier to debug and analyse. I could pinpoint where I was going wrong much more quickly. Events are a no-brainer in free-flowing games though, where you have multiple instances of objects interacting with other objects on the fly (in a simple way). But it's worth knowing that it can obscure your code somewhat on bigger projects. Pretty much everything in Unity/C# has it's strengths and weaknesses, and events are no different.
i gotta say, delegates are probably the most useful thing there is in c#. Being a javascript guy, i always hate to take the procedural approach in problems where map, filter, reduce and higher order functions can be used. But i have to say, the type safety introduces a lot of verbosity D:
I just don't understand the part where he passes in scoreCalculator at 5:30, can someone please explain? There is no function that's defined, so what's happening?
I know this is 4 months old, but scoreCalculator is just the name for the delegate and an integer is what gets passed in because at the top of the code is the delegate with the integer type. Hope I explained this well enough for you
the way i see it is that the only two uses for delegates are to make the input or output of a function be itself a function,(an example of which is shown in this video), and using them as events. Is there an example of a situation where it would be appropriate to call an event instead of calling all the functions i know to be listening to the event directly?
So, in short, delegates are like variables for storing and invoking methods? Int x = "Hello world!" // Doesn't work delegate void DelegateTest(); string StringReturnMethod(){ return "Hello world!" } DelegateTest myDelgate = StringReturnMethod; // Also doesn't work Fascinating... ^^
I believe I have encountered a problem with delegates. They only work if there is only ONE instance of the object. The other ones will do what the first instace does.
Do you have a time table for the Lambda episode? I'm having trouble understanding them myself, that or a link to a good explanation of them would be terrific. Thanks!
I don't have any immediate plans for the lambda episode. You might find Jamie King's video on the topic helpful: ruclips.net/video/KRjeu9Thp3s/видео.html
I'm having trouble understanding the foreach statement.. why is 'stats' allowed when it was not declared.?? is it because of the 2nd parameter scorecalculator??
Is there a specific reason why you wouldn't use LinQ for this? Or did you just need an example for Delegates? Just interested, maybe LinQ is more expensive or something. string playerNameMostKills = allPlayerStats?.Max(i => i.kills)?.name ?? "Unknown"; string playerNameMostFlagCaptured = allPlayerStats?.Max(i => i.flagsCaptured)?.name ?? "Unknown";
i'm gonna throw my two cents out there, but i don't know how safe it is to use linq in unity. LinQ is probably more expensive in a lot of cases, and some options don't work on some platforms, though it's most definitely not the case with the example given. One thing i have to ask, are the ? thrown in there the null-conditional operator?
didn't explain the basis of it, just the method of it. He jumped to passing a delegate as a parameter without a by-your-leave as if it was everyday thing
![[C#] Delegates and Events (E02: events)](http://i.ytimg.com/vi/TdiN18PR4zk/mqdefault.jpg)
![[C#] Delegates and Events (E02: events)](/img/tr.png)
6:50 Magic happening :D.
Love when people explain by simply showing how it works, how we do without, and it's much better with.
This way you not only understand quicker, but you actually want to use the feature.
Excellent video.
in other words, delegates are simply reference variables. They hold any number of methods as a reference (as long as the signatures match)
thanks bro
this is the quickest yet most understandable tutorial i've found
the same @sebastian is the beast!!!
No it is not. What IS a delegate?
Nobody knows after watching this video. Useless.
@@bobsagget823 I had a hard time understanding it, but I eventually did. He teaches really fast at times, so the more experience you have, the better. But yeah if I were a beginner this would fly far above my head.
Would have been better an example with an event system. For example, when you click a button on UI, you turn all gameobjects to a random color which are subsribed to the event.
For those who are familiar with C, creating a delegate type is the same as creating a typedef for a function pointer. When declaring a delegate, you essentially declare a pointer of that type and assign the function address to it. When invoking a delegate, you indirectly call the function using the pointer. This of course lets you create arrays of delegates making for fast decoding and program flow. You can also have delegates "pointing" to array of delegates making for even more complex decoding.
Thank you
Hello, I hope you enjoy this mini-series on delegates and events. The second part should be out in a day or two.
If you'd like to translate this video, you can do so here: ruclips.net/user/timedtext_video?ref=share&v=G5R4C8BLEOc
Dude, its awesome. I wish I saw this video like few years ago, when I was trying to figure out what the hell it is, all those delegates and lamba expressions :D
This video is extremely helpful and easy to understand (imo)
I already learned about those before... But I never actually used them so now at least I will have reference to this whenever I forget something about events, as this is my favourite Unity tutorial channel so far.
EDIT: that scoring example was literally best I've ever seen.
Isn't it FUBAR?
Not in programming :)
en.wikipedia.org/wiki/Foobar
I made a spanish translation for your video :D
Teaching is a talent. thats why Sebastian's videos are so wonderful. he is a great teacher.
I'm still trying to wrap my head around delegates, but I think you've explained them enough for me to try on my own. Thanks again for a wonderful tutorial, Sebastian!!!
Wow. Some people are gifted at taking troublesome topics and explaining them such that they seem simple. Thank you and very well done.
It was the best explanation on delegates that i have seen
The only good video about delegates I found on YT. Everyone else is too busy gibbering the way they understood this concept instead of actually explaining it with clear examples. Good job.
Awesome. A nice and clear way to explain why and how I should use delegates. Always wondered about them.
Very down to earth explanation, wish I had seen something like this back in my freshman days.
Delegates are a way to parameterize behaviour instead of just values. The way you used it here is perfect example of a functor in real life. C# was a pioneer in implementing these kind of patterns in the language by avoiding a plain old pointer while at the same time actually using one behind the scenes
I have to say. I probably watched 10 or 15 tutorials about delegates and events in c#. This is by far the most effective and clear one. I think that most the coding RUclipsrs don't understand that when we want to learn something new, especially in programming where are so many layers of context, we want to learn in the simple way possible. And what I see most of the time, is the content creator explaining the thing that we want to learn attached to 20/30 other things that are not needed to explain this new thing that we want to learn. First, we ONLY want to learn the new tool, ONLY after that, we can try to apply that new tool to new contexts...So, Thank you for making a good example of what a tutorial must be. Congrats
Thank you very much, I've been programming for almost 3 years now but I never understood delegates. You explained it so clear that finally i learned what delegates are :D
THANKS GOD other tutorials are like 30 mins boring and complex examples, but this one is amazing!!! Thank you so much!!!!!!!!!!!
THIS IS THE BEST VIDEO ON YT I HAVE EVER SEEN EXPLINING DELEGATES, Thank you learning this part was relly frustrating
Your two videos for Delegates and Events are the absolute best explanation in the internet. Thank you for this.
I found a fault in your video.
You didn't introduce yourself with a 'HEEEEEYYY WHAT'S UP GUYS, THIS IS SEB, MY PATREON SUBCRIBE LIKES' etc
THANK GOD. Was tempted and decided ya know what...the 50 ish minutes he saved me by explaining clearly in 7 minutes instead of an hour with no HEY! WHAT"S UP hyper stuff is worth $5 right there. One time patreon x => x+5
I really liked the examples. Straightforward, excellent explanation. Thank you.
Definitely the best explanation of delegates i ever seen
This is one of the best delegate tutorial i have ever seen. Please keep more detailed tutorials about programmming. You ara awasome and thank you!
Your tutorial put everything together for me and everything just 'clicked' cheers..Thank you, Sebastian much appreciated!
Your videos are extremely professional and clean. The only problem I have is that you are so concise about what you say, that if I blink for a second a miss an important bit of information. Maybe you could take it just a tad slower. My brain would be very thankful. Great channel, already subscribed!
Thank you, i've watched a lot of videos but this is the one that got to me. Simple how it works and why should you use it . Thank you .
I've been finding C# tutorial about delegates for so long
Thx God, I found yours.
After watching this, Delegates seems very easy.
jesus christ. so many years of not knowing this. thankyou Sebastian
Thank you so much for this video!
I never thought about using delegates like that to be honest, i used to just use them in the most basic way to call multiple functions at once, always simply thought of them as event broadcasters. This combined with the lambda expression is going to make some of my code a lot cleaner and less boiler platey, thanks again! :3
I really liked this format for explaining concepts in C#. Top quality stuff
Best Delegate video I’ve seen. Nice job.
where was this 2 semesters ago, nicely done as always
Huh! This a very interesting different way to approach this,you are essentially doing Parameter injection on the function. Giving it the implementation of scoreCalculator you really want when calling it.
Thank you Sebastian! Another excellent tutorial. Looking forward to the part two. And really looking forward to a bigger more in depth tutorial on lambda expressions!
This is the third time I watched the video and I still couldn't follow, I'll watch several more times but I think I should read more document about it before pushing this thing into my head. I just have to learn this because it's needed for my game, it make life easier this way too.
Exactly how I feel! It is a good example but just isn't clicking.
I love this video so much. This channel is a real gem.
this man knows how to explain
finally excellent use case for delegate usage
It's pretty cool, Lambda expressions are useful ,but variable initialization should be considered when passing functions because not only do you have to worry what's being put on the stack ,but the reinitialized variables can cause latency issues unless dealt with properly. Of course the instance you showed was perfectly fine because that isn't repeating unnecessary code . Good Job Sebastian!! I have high hopes for this mini-series!!
clean and simple... bravo!!! Thank you very much!
Excelent video!. My question is: why would I use a delegate instead of calling the function 'GetPlayerNameTopScore' twice with different arguments?
That's very helpful!
I had some trouble comprehending some of these concepts, but that clears things a lot.
Wow, your tutorials are excellent learning tools. Thankyou for making these videos.
You are my hero, love your heap explanation from another video
I'm always a bit confused about the differences between Lambda expressions, delegates and events (the things of the type "Action")
But still I use Events for my Attack class. Each Attack has an impact-, hit- and activation-Event that is called within Invoke() of the Attack class. When the attack impacts on anything, hits a mortal-target or is activated it publishes the corresponding event with parameters like impactPoint, caster, hitObject etc... . The gain in this is that when i define an attack, i can put whatever function i like into those events or nothing at all. Therefore my utility-attacks use the same class and therefore Invoke as my spell-attacks, the only difference is that when i create the utility-attack i supply an activation effect only (e.g. instantiate some arbitrary game object like a lava patch) while on a normal attack i might define only a hit or impact effect.
Without that i would have to create a new function for every single effect my spells might exert. I would have to have a specific function that creates a lava-patch within the Attack class but now i just write "spellLavaPatch.impactEffect (dir, caster, pos) => { CreateSpellObjectbyPrefab(lavaPatch, pos); }" when i define the attack and the creation is neatly included when i call "spellLavaPatch.Invoke(dir, caster);" anywhere
At least that's what i do as of now, for me it is the first time utilizing those things.
How the hell do I subscribe twice man I actually understand delegates now after scouring the entire internet for a half decent explanation
Amazing tutorial. I want to go over some of my old code and rewrite it now
You're the best, keep posting please!
Excellent Tutorial
Be blessed man.
Where did the "stats" come from?
Would it make sense to compare delegates in C# too callback functions in JS/TS? Are there any important discrepancies between the two?
First time I've ever fully grasped lambda expressions
Delegates is implemention of Delphi 'function of object' (well, it's Anders Hejlsberg after all...). It's kinda logical as using of pointers was declared 'unsafe' but programmers still need to get an access to methods.
Thanks for sharing, had no idea you could do something like this. Might take a while to get my head around before I start using it naturally in practice but it seems helpful :)
Also you might want to name this episode Delegates, then the next episode Events. Like having it as 2 separate episodes rather than a short series? Just an idea :) Cheers.
Hi, glad you found it helpful!
I chose to make this a 2-part series because it makes a lot of sense to learn about delegates and events at the same time (given that events are simply delegates with a few restrictions). I've edited the title to clarify that this episode only covers delegates though. Cheers :)
Sebastian Lague ah right that makes sense then, I had no idea what an Event was so I just imagined it was something completely different :)
Thank you for the help! This was very great and is going to help me pass my c# test!
Events are great, but in some cases standard method calling can be more suitable - especially if you're making a strictly turnbased tactical game with an AI Sequence for example. I personally found that being able to see the methods being explicitly called within a complex algorithm (spread over several scripts) made it far, far easier to debug and analyse. I could pinpoint where I was going wrong much more quickly.
Events are a no-brainer in free-flowing games though, where you have multiple instances of objects interacting with other objects on the fly (in a simple way). But it's worth knowing that it can obscure your code somewhat on bigger projects.
Pretty much everything in Unity/C# has it's strengths and weaknesses, and events are no different.
i gotta say, delegates are probably the most useful thing there is in c#. Being a javascript guy, i always hate to take the procedural approach in problems where map, filter, reduce and higher order functions can be used. But i have to say, the type safety introduces a lot of verbosity D:
what is the color pattern you are using for you code in this video, i really like it!
Really good example, my code finally works!
Remember me ? Good news! I successfully understand this thing and E02: events. About a week huh ? Well at least it's paid off :D
thank you so much! noob as i can learn a lot from this.
I don't understand this video that well, how do ScoreByKillCount and ScoreByFlagCaptures know about the delegate?
Great video and a good refresher from some stuff I learned in school. Keep it up.
Best explanation for delegates...and yet I stil need time to digest this :D
Nice explanation.
Awesome, can't wait for the next one!
I would love to see some tutorials on Editor Scrips in the future. Keep it up!
Really good stuff, as always
I am new to all of this, so do delegates optimize the code making it less redundant?
Thank you so much!!! I finally get it!
I just don't understand the part where he passes in scoreCalculator at 5:30, can someone please explain? There is no function that's defined, so what's happening?
I know this is 4 months old, but scoreCalculator is just the name for the delegate and an integer is what gets passed in because at the top of the code is the delegate with the integer type. Hope I explained this well enough for you
Really good. Thanks
Sorry, but can You explain in depht what it is "stored" inside the myDelegate(50) at timestamp 02:36 line 11?
thanks for these videos man! Very helpful.
Never knew about these thanks for the lesson!
thank you sebastian
Thanks, dude.
the way i see it is that the only two uses for delegates are to make the input or output of a function be itself a function,(an example of which is shown in this video), and using them as events.
Is there an example of a situation where it would be appropriate to call an event instead of calling all the functions i know to be listening to the event directly?
So, in short, delegates are like variables for storing and invoking methods?
Int x = "Hello world!" // Doesn't work
delegate void DelegateTest();
string StringReturnMethod(){
return "Hello world!"
}
DelegateTest myDelgate = StringReturnMethod; // Also doesn't work
Fascinating... ^^
Codes are become more and more intriguing as if some extraterrestrial are developing ✍️
You might want to rename this episode to *just* delegates, since that is the only thing that you covered in this episode :P
Hi, nice tutorials as always. I was wondering if you actually have finished a complete game?
nicely explained!
OH MY GOD! I understood delegates in under 7 minutes!
Great video!
Thanks, you made my life easier again :D
I believe I have encountered a problem with delegates. They only work if there is only ONE instance of the object. The other ones will do what the first instace does.
Could you tell me the theme and font you use for your editor? It looks really nice.
Thanks for english sub-title. :)
Eu não sei quem foi mas um filho de Deus coloco a tradução pra pt br e não a do google tradutor que né ,obrigado cidadão.
Hi. I would really appreciate a tutorial on how to do this in unity.
actually we can assume than a delegate is a kind of class or in use of class at the same time
For what it is worth... it is actually F.U.B.A.R. (short for F'ed Up Beyond All Recognition)
But steel is heavier then feathers? I don't get it.
Do you have a time table for the Lambda episode? I'm having trouble understanding them myself, that or a link to a good explanation of them would be terrific. Thanks!
RUclips has some good tutorials on that, anyway, he didn't make that video yet.
I don't have any immediate plans for the lambda episode. You might find Jamie King's video on the topic helpful:
ruclips.net/video/KRjeu9Thp3s/видео.html
Beautiful.
I'm having trouble understanding the foreach statement.. why is 'stats' allowed when it was not declared.?? is it because of the 2nd parameter scorecalculator??
@3:45 stats is being declared while in use
What happend to lambdas? Cant see a video about them
Is there a specific reason why you wouldn't use LinQ for this? Or did you just need an example for Delegates? Just interested, maybe LinQ is more expensive or something.
string playerNameMostKills = allPlayerStats?.Max(i => i.kills)?.name ?? "Unknown";
string playerNameMostFlagCaptured = allPlayerStats?.Max(i => i.flagsCaptured)?.name ?? "Unknown";
No, it's just for the sake of the example.
Fair enough! Keep up the great content!
i'm gonna throw my two cents out there, but i don't know how safe it is to use linq in unity. LinQ is probably more expensive in a lot of cases, and some options don't work on some platforms, though it's most definitely not the case with the example given. One thing i have to ask, are the ? thrown in there the null-conditional operator?
sounds very similar to passing the reference of a function
do more stuff like this....Thanks :)
didn't explain the basis of it, just the method of it. He jumped to passing a delegate as a parameter without a by-your-leave as if it was everyday thing