PHP-and-MySQL/C4/PHP-String-Functions-Part-2/English-timed
From Script | Spoken-Tutorial
| Time | Narration |
| 00:00 | Ok. Back to the second part of the String Functions tutorial. |
| 00:03 | I'm going to go through the rest of the functions starting from String Reverse. |
| 00:08 | String reverse probably to make sense is s-t-r-rev. |
| 00:11 | So, what strvev() does is it reverses the contents of a string. |
| 00:20 | So if I were to say 'Hello' and I were to reverse that, it would be "o-l-l-e-H". |
| 00:30 | And it can be useful in some circumstances although you usually wouldn't use this. |
| 00:36 | But you could use this function if you want to specifically reverse a string. |
| 00:41 | I think it's a useful and fun function to use. |
| 00:45 | Ok - the next set of functions I have grouped together are these: str to lower() and str to upper(). |
| 00:54 | This basically means string to lower case and string to upper case. |
| 00:58 | So, if we have our '$string' that equals 'HELLO', I can say echo str to lower and show the value of the $string in here. |
| 01:12 | The 'HELLO' in capitals will now become lowercase. |
| 01:15 | Something similar would happen if I were to say this is 'hello' in small case. |
| 01:21 | And I could say str to upper and that would give me my uppercase version of the string. |
| 01:31 | Now, one applicable use of this is when you have user-registration. |
| 01:35 | If you have a website on which users have to register, you should usually always store the user name as a lower string. |
| 01:49 | The reason is that if I submit a user name - let's get rid of this... |
| 01:55 | Some people actually do this - Let's have a variable user name which equals say 'ALEX'. |
| 02:01 | And I'll put in these also - uppercase and small case alphabets. |
| 02:07 | Some people use names like this to make the name look funky and its perfectly okay. |
| 02:13 | But if the name is stored as this and you think - well did I start with a small 'a'? |
| 02:19 | Then I have another pattern for username now. |
| 02:23 | So, what you can do is say $stored user name equals to str to lower of the $username. |
| 02:29 | So, this would be the stored username in the database. |
| 02:33 | Now, when they go to login and type in their 'username' in this combination, what we would do is we would convert their typed-in login 'username' to lower case and compare it to the lower case stored version of the 'username'. |
| 02:48 | So, we are taking this and storing a lowercase value inside the database and we are comparing it to a typed-in value which has also been converted to lower case. |
| 02:58 | Hence, we can't go wrong and users are not going to forget their user-names. |
| 03:07 | You could do the same with passwords. |
| 03:14 | Ok. let's go to the next one. |
| 03:22 | Sub-string count. This would basically count the no. of sub-strings matching to a particular value inside a string. |
| 03:31 | So, here I'll type $search equals "My name is alex. What is your name?". |
| 03:37 | So, this is our string. |
| 03:41 | Now, if I say we need to echo out the sub-string count()... |
| 03:49 | and obviously this stands for sub-string-count, what we want to do is, we want to search our '$search' string... |
| 04:01 | and we will specify a string to search for. Now this will return an integer if we put this in a variable called $result. |
| 04:12 | That's because you can't find any instance of a word which will appear say for 1.2 times. |
| 04:20 | Also the variable result will not return 2 as t-w-o. It will only return 2 as an integer. |
| 04:30 | So, this is quite useful if we are using substring count() to search for, lets say, 'alex'. |
| 04:36 | And then it will echo out on its own. |
| 04:39 | And if you look through here, you will see there is only one instance of 'alex'. |
| 04:44 | So, refresh that - and we should get the number 1. |
| 04:46 | Now if we were to search for 'name' - there's 1 instance of 'name' here and another instance of 'name' here. |
| 04:52 | So, when we refresh, we should get the value 2. |
| 04:55 | Now there are optional parameters for this which are 'where to start from in a string' and 'where to end in a string'. |
| 05:02 | Let's try this out. |
| 05:05 | So let's say- I want to search from after "name", ok? |
| 05:11 | So this is 0 1 2 3 4 5 6. |
| 05:14 | So, I say search "name" from 7 onwards. |
| 05:19 | So, search "name" from 7 and it will search in this blue area that I have highlighted here. |
| 05:25 | It will only return 1 in the result. |
| 05:28 | So, you can specify whereabouts in the string. |
| 05:30 | I think you can specify up to where. |
| 05:33 | So this is 7... 8 9 10 11 12 13 14 15 16. |
| 05:43 | 7 to 17. Let's check if this works. |
| 05:46 | It shows zero. So from 7 to 17 - which is from about here to here - we find zero instances of 'name'. |
| 05:55 | However if we search for 'alex', we will find 1 instance of it. |
| 06:01 | Ok - so that's the substring count() function. |
| 06:07 | And now substring replace() is similar. |
| 06:12 | It's not the same function but it includes an added bonus where you can replace your string. |
| 06:18 | So the replace tags are - My name is alex and I've added the full-stop on purpose. |
| 06:28 | Our $result is equal to substring replace(). |
| 06:33 | What do I want to replace in? I want to replace in the variable $replace. |
| 06:41 | And I want to replace 'alex' with 'billy'. |
| 06:48 | And this will be from - let me count 0 1 2 3 4 5 7 8 9 10 11 so from 11 until... |
| 07:01 | It's 11 - 0 1 2 3 4 5 6 7 8 9 10 11 - from 11 to 14. |
| 07:14 | So that should replace 'alex' with 'billy'. |
| 07:19 | Replace and refresh. |
| 07:21 | Oh! We didn't echo out $result. |
| 07:23 | Let's echo out $result and we can refresh this. |
| 07:26 | And it should return my name is "billy". |
| 07:30 | This should be 12 and this 15, I think. |
| 07:34 | Or in fact no - it should be 10 and 14. |
| 07:38 | No, not quite right.... We are missing the full-stop. |
| 07:43 | ........ so let's go for 11 and 14. |
| 07:49 | Still missing the full stop and I cant think why. |
| 07:52 | Aah! well you get the picture. |
| 07:55 | Basically you can replace anything in the string with the starting value and the ending value. |
| 07:59 | It will leave it up to you to count through. |
| 08:04 | I'm very tired, so I am not able to count. |
| 08:09 | So, what we are doing here is we are replacing a particular string with a particular value. |
| 08:14 | And here's your starting value and here's your finishing value. |
| 08:17 | That's all in this tutorial. |
| 08:19 | There are many more string functions and I suggest you to search, may be, on 'google'. |
| 08:24 | Search for 'php string functions' and you'll find a lot of interesting functions. |
| 08:28 | If you are looking to do a particular thing there's probably a function available for it. |
| 08:33 | Thanks for watching! This is Osama Butt, dubbing for the Spoken Tutorial Project. |
