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