Difference between revisions of "PHP-and-MySQL/C2/Loops-While-Statement/English-timed"

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|Hello and welcome. I have decided to create separate tutorials for each looping '''statement'''.
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|Hello and welcome. I have decided to create separate tutorials for each '''loop'''ing '''statement'''.
  
 
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|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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|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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|In this tutorial, we will learn about the '''while''' loop.
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|In this tutorial, we will learn about the ''''while' loop'''.
  
 
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|A '''while''' loop checks for a '''condition''' at the start of the loop and executes the code depending on whether this '''condition''' is '''True''' or not.
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|A '''while''' loop checks for a '''condition''' at the start of the loop and '''execute'''s the '''code''' depending on whether this '''condition''' is '''True''' or not.
  
 
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|My '''condition''' is here.  Now, in the '''if''' statement, for example I used 1==1.
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|My '''condition''' is here.  Now, in the '''if''' statement, for example I used '''1==1'''.
  
 
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Latest revision as of 21:11, 15 December 2018

Time Narration
00:00 Hello and welcome. I have decided to create separate 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 of 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 my 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 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, let's try this.
01:22 It would probably crash your browser because the loop would be repeated as long as 1=1 and for infinite number of times, 1 will always equal to 1.
01:34 So, since the loop will always be repeated, your browser will crash.
01:40 Let's say while a variable '$num' is smaller or equal to 10 and under echo I can say: $num ++.
01:57 '++' is an arithmetical operator. What it basically does is, it increases 'num' by 1. It is the same as writing 'num =num +1'.
02:16 So, it takes 'num' and says that it is equal to the value of 'num plus 1'.
02:23 So, this again is an arithmetical operator. What's going to happen is -
02:29 we are going to say 'num' less than or equal to (<=) 10; if 'yes' then echo Loop and then say add 1 on to the variable 'num'.
02:41 But, what we should really do is create '$num = 1' at the moment. So Loop once at 1. This will then equals to 2, then 3, then 4, then all the way up to 10 and then this 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 we will we get. Okay, we got 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 '$num' inside - it will make it much easier to read.
03:37 Okay. I'll say loop 1 and add 1 and then I'll say loop 2 and I'll add another 1; and that's loop 3 and I'll add another 1 up to 10.
03:49 Let's open this up. Refresh it. There you go. You got loop 1,2,3 all the way up to 10 as you can see.
03:58 Let's change this value here to 100. Refresh that. You can see it has gone to hundred. The bigger the number, the longer it will take to loop.
04:08 Let's take 6000. Let's refresh that. It's going to take a while. There you go - up to 6000. So it's very efficient in this way.
04:20 You can try combining this with an array to create a program that echoes out the alphabets inside the array.
04:27 You can use loop to echo out every single value of an array.
04:32 Just give it a go. I will probably do this in one of my tutorial - not in the basics section though.
04:40 However, this is the basic structure. What I also recommend you to do is, create a variable here called '$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 summarize. 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.

Contributors and Content Editors

Minal, PoojaMoolya, Pratik kamble, Sandhya.np14