Difference between revisions of "PHP-and-MySQL/C2/Loops-While-Statement/English-timed"
From Script | Spoken-Tutorial
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| − | | | + | |00:00 |
|Hello and welcome. I have decided to create seperate tutorials for each looping statement. | |Hello and welcome. I have decided to create seperate tutorials for each looping statement. | ||
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| − | | | + | |00:07 |
|I want to keep it simple. This will be useful as a reference also if you need to refer to how a particular loop works. | |I want to keep it simple. This will be useful as a reference also if you need to refer to how a particular loop works. | ||
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| − | | | + | |00:17 |
|In this tutorial, we will learn about the WHILE loop | |In this tutorial, we will learn about the WHILE loop | ||
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| − | | | + | |00:21 |
|A WHILE loop checks for a condition at the start at the loop and executes the code depending on whether this condition is True or not | |A WHILE loop checks for a condition at the start at the loop and executes the code depending on whether this condition is True or not | ||
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| − | | | + | |00:38 |
|for example I'll start my 'WHILE loop' here and this is the condition and this is my block. | |for example I'll start my 'WHILE loop' here and this is the condition and this is my block. | ||
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| − | | | + | |00:51 |
|I'll represent my block between curly brackets. | |I'll represent my block between curly brackets. | ||
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| − | | | + | |00:56 |
|My condition is here. Now, in the 'IF statement', for example I used 1==1. | |My condition is here. Now, in the 'IF statement', for example I used 1==1. | ||
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| − | | | + | |01:04 |
|Now if I say 'test' or 'loop' here. | |Now if I say 'test' or 'loop' here. | ||
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| − | | | + | |01:07 |
|This is a loop here and then a break. Now what happens is as long as 1=1, it would create a loop | |This is a loop here and then a break. Now what happens is as long as 1=1, it would create a loop | ||
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| − | | | + | |01:17 |
|If I do something here, lets try this. | |If I do something here, lets try this. | ||
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| − | | | + | |01:22 |
|It would probably crash your browser because the loop would be repeated as long as 1=1 and for infinite no. of times, 1 will always equal 1. | |It would probably crash your browser because the loop would be repeated as long as 1=1 and for infinite no. of times, 1 will always equal 1. | ||
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| − | | | + | |01:34 |
|So since the loop will always be repeated, your browser will crash. | |So since the loop will always be repeated, your browser will crash. | ||
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| − | | | + | |01:40 |
|Lets say while a variable, 'num' is smaller or equal to 10 and under echo i can say - 'num ++' | |Lets say while a variable, 'num' is smaller or equal to 10 and under echo i can say - 'num ++' | ||
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| − | | | + | |01:57 |
| '++' is an arithmetical operator. And what it basically does is, it increases num by 1. It is the same as writing 'num =num +1' | | '++' is an arithmetical operator. And what it basically does is, it increases num by 1. It is the same as writing 'num =num +1' | ||
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| − | | | + | |02:16 |
|So it takes num and says that it is equal to the value of num plus 1. | |So it takes num and says that it is equal to the value of num plus 1. | ||
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| − | | | + | |02:23 |
|So this again is an arithmetical operator. What's going to happen is - | |So this again is an arithmetical operator. What's going to happen is - | ||
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| − | | | + | |02:29 |
|We are going to say 'num' lesser than or equal to '10', if yes then echo loop and then say add 1 on to the variable num | |We are going to say 'num' lesser than or equal to '10', if yes then echo loop and then say add 1 on to the variable num | ||
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| − | | | + | |02:41 |
|But what we should really do is create 'num = 1' at the moment. So loop once at 1. This will then equal 2 then 3 then 4 all the way up to 10 and then it will stop | |But what we should really do is create 'num = 1' at the moment. So loop once at 1. This will then equal 2 then 3 then 4 all the way up to 10 and then it will stop | ||
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| − | | | + | |03:01 |
|After that the rest of the code below this will continue. | |After that the rest of the code below this will continue. | ||
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| − | | | + | |03:06 |
|So we said this 1 and see what will we get. Okay we got a loop 1,2,3,4,5,6,7,8,9,10 times | |So we said this 1 and see what will we get. Okay we got a loop 1,2,3,4,5,6,7,8,9,10 times | ||
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| − | | | + | |03:20 |
|Now to make it more fun I'll say loop 1 and I'll concatenate 'num' to the end of that | |Now to make it more fun I'll say loop 1 and I'll concatenate 'num' to the end of that | ||
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| − | | | + | |03:27 |
|In fact let's make it simpler and say 'num' inside - it will make it much easier to read | |In fact let's make it simpler and say 'num' inside - it will make it much easier to read | ||
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| − | | | + | |03:37 |
|Okay I'll say loop 1 and add 1 and then I'll say loop 2 and I'll add another 1; that's loop 3 add another 1 up to 10. | |Okay I'll say loop 1 and add 1 and then I'll say loop 2 and I'll add another 1; that's loop 3 add another 1 up to 10. | ||
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| − | | | + | |03:49 |
|Lets open this up. Refresh it. There you go. You got loop 1,2,3 all the way up to 10 as you can see | |Lets open this up. Refresh it. There you go. You got loop 1,2,3 all the way up to 10 as you can see | ||
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| − | | | + | |03:58 |
|Lets change this value here to 100. Refresh that. You can see it has gone to hundred. The bigger the number, the longer it will take to loop | |Lets change this value here to 100. Refresh that. You can see it has gone to hundred. The bigger the number, the longer it will take to loop | ||
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| − | | | + | |04:08 |
|Let's take 6000. Let's refresh that. It's going to take a while. There you go - up to 6000. So it's very efficient in this way | |Let's take 6000. Let's refresh that. It's going to take a while. There you go - up to 6000. So it's very efficient in this way | ||
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| − | | | + | |04:20 |
|You can try combining this with an 'array' to create a program that echoes out of the alphabet inside the 'array' | |You can try combining this with an 'array' to create a program that echoes out of the alphabet inside the 'array' | ||
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| − | | | + | |04:27 |
|You can use loops to echo out every single value of an array | |You can use loops to echo out every single value of an array | ||
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| − | | | + | |04:32 |
|Just give it a go. I will probably do this in one my tutorial - not in the basics section though | |Just give it a go. I will probably do this in one my tutorial - not in the basics section though | ||
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| − | | | + | |04:40 |
|However, this is the basics structure. What I also recommend you to do is create a variable here called 'max' and put your maximum value here | |However, this is the basics structure. What I also recommend you to do is create a variable here called 'max' and put your maximum value here | ||
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| − | | | + | |04:53 |
|This will do exactly the same thing. It's just a lot more easy to read and you can declare all this here and this would be a reference to it | |This will do exactly the same thing. It's just a lot more easy to read and you can declare all this here and this would be a reference to it | ||
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| − | | | + | |05:03 |
|If you have more than 1 loop. I prefer it for readability and flexibility for my program. Okay so that's a WHILE loop. Let me summarise. It checks the condition of the start | |If you have more than 1 loop. I prefer it for readability and flexibility for my program. Okay so that's a WHILE loop. Let me summarise. It checks the condition of the start | ||
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| − | | | + | |05:17 |
|If the condition is True. it would execute this block of code and you can do things like 'echo alpha' | |If the condition is True. it would execute this block of code and you can do things like 'echo alpha' | ||
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| − | | | + | |05:24 |
|Your variable is being incremented. Make sure that you do increment your variable otherwise it will loop for infinity. | |Your variable is being incremented. Make sure that you do increment your variable otherwise it will loop for infinity. | ||
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| − | | | + | |05:32 |
|Thanks for watching. This is Sidharth for the Spoken Tutorial Project, signing off. Goodbye. | |Thanks for watching. This is Sidharth for the Spoken Tutorial Project, signing off. Goodbye. | ||
Revision as of 11:15, 10 July 2014
| Time | Narration |
|---|---|
| 00:00 | Hello and welcome. I have decided to create seperate tutorials for each looping statement. |
| 00:07 | I want to keep it simple. This will be useful as a reference also if you need to refer to how a particular loop works. |
| 00:17 | In this tutorial, we will learn about the WHILE loop |
| 00:21 | A WHILE loop checks for a condition at the start at the loop and executes the code depending on whether this condition is True or not |
| 00:38 | for example I'll start my 'WHILE loop' here and this is the condition and this is my block. |
| 00:51 | I'll represent my block between curly brackets. |
| 00:56 | My condition is here. Now, in the 'IF statement', for example I used 1==1. |
| 01:04 | Now if I say 'test' or 'loop' here. |
| 01:07 | This is a loop here and then a break. Now what happens is as long as 1=1, it would create a loop |
| 01:17 | If I do something here, lets try this. |
| 01:22 | It would probably crash your browser because the loop would be repeated as long as 1=1 and for infinite no. of times, 1 will always equal 1. |
| 01:34 | So since the loop will always be repeated, your browser will crash. |
| 01:40 | Lets say while a variable, 'num' is smaller or equal to 10 and under echo i can say - 'num ++' |
| 01:57 | '++' is an arithmetical operator. And what it basically does is, it increases num by 1. It is the same as writing 'num =num +1' |
| 02:16 | So it takes num and says that it is equal to the value of num plus 1. |
| 02:23 | So this again is an arithmetical operator. What's going to happen is - |
| 02:29 | We are going to say 'num' lesser than or equal to '10', if yes then echo loop and then say add 1 on to the variable num |
| 02:41 | But what we should really do is create 'num = 1' at the moment. So loop once at 1. This will then equal 2 then 3 then 4 all the way up to 10 and then it will stop |
| 03:01 | After that the rest of the code below this will continue. |
| 03:06 | So we said this 1 and see what will we get. Okay we got a loop 1,2,3,4,5,6,7,8,9,10 times |
| 03:20 | Now to make it more fun I'll say loop 1 and I'll concatenate 'num' to the end of that |
| 03:27 | In fact let's make it simpler and say 'num' inside - it will make it much easier to read |
| 03:37 | Okay I'll say loop 1 and add 1 and then I'll say loop 2 and I'll add another 1; that's loop 3 add another 1 up to 10. |
| 03:49 | Lets open this up. Refresh it. There you go. You got loop 1,2,3 all the way up to 10 as you can see |
| 03:58 | Lets change this value here to 100. Refresh that. You can see it has gone to hundred. The bigger the number, the longer it will take to loop |
| 04:08 | Let's take 6000. Let's refresh that. It's going to take a while. There you go - up to 6000. So it's very efficient in this way |
| 04:20 | You can try combining this with an 'array' to create a program that echoes out of the alphabet inside the 'array' |
| 04:27 | You can use loops to echo out every single value of an array |
| 04:32 | Just give it a go. I will probably do this in one my tutorial - not in the basics section though |
| 04:40 | However, this is the basics structure. What I also recommend you to do is create a variable here called 'max' and put your maximum value here |
| 04:53 | This will do exactly the same thing. It's just a lot more easy to read and you can declare all this here and this would be a reference to it |
| 05:03 | If you have more than 1 loop. I prefer it for readability and flexibility for my program. Okay so that's a WHILE loop. Let me summarise. It checks the condition of the start |
| 05:17 | If the condition is True. it would execute this block of code and you can do things like 'echo alpha' |
| 05:24 | Your variable is being incremented. Make sure that you do increment your variable otherwise it will loop for infinity. |
| 05:32 | Thanks for watching. This is Sidharth for the Spoken Tutorial Project, signing off. Goodbye. |
