Beginner PHP Tutorial - 54 - Creating a Find and Replace Application Part 1 Video Lecture | PHP for Absolute Beginners: From Novice to PHP Master - Web Development

hi this is Alex from PHP academy' org
and this is a video tutorial for the new
Boston now in this video we're going to
be creating a web application if you
like or a script that works in a similar
way to this now we have a text box here
in which we can type any data so I'm
going to say the cat sat on the mat in
this box here I can search for a string
that I want to replace in particular and
then I want to specify what are to
replace it with so let's say I wanted to
search for Cat Cat exists here in the
string so I want to replace it with
let's say dog or let's say monkey yeah
speak things fun so now I'm going to
click find a replace and you'll see that
cat is replaced with the string monkey
okay
so we already know in PHP that we can
use the AB STR underscore replace
function and this allows you to specify
either an array or a single string to
replace now let's just open up my text
editor and I'll demonstrate this for you
ok so STR replace works by taking the
string you want to replace the data in
so the overall string which in this case
would be the text in this box here then
what we'll do is we would search for the
string that we want to search for so
search and in this case it would
correspond to this here then what we
would do is we would specify what we
want to replace it with and that would
correspond to this box here
however this tutorial is dealing with
the substring
a function and this function works in a
similar way that has a combination of
technique and what we do in this
function I have another video on this so
if you want to go back and refer to that
is we have strengths or our overall
string once again what you want to what
you want to replace so for example in
this case we will be supply monkey in
there because we're choosing to replace
with monkey and then we would choose the
position the start position that we'd
want to start replacing up so in this
case let's go back to the original
example of a cat sat on the mat it would
be 0 1 2 3 we'd be starting at the third
position
so we'd Pier 2 2 3 and there we then say
how many characters we want to cut off
and then add this string in so in this
case it would be 3 also because we want
to get rid of 3 characters starting from
the third position and we want to
replace that with the text monkey and
this will be shifted along to above and
allow you you know to have more than one
more than three characters so obviously
monkeys at six characters so in this
example I use the substring replace
function where I could have just used
STR replace now the reason I'm doing
this is simply to demonstrate the use
that substring function can have if you
wanted to create um a script that did
this you could just use the string
replace function and you would be able
to use it in the way I've already talked
about however I'm going to go the long
way around things in this tutorial and
talk about how we're using the substring
replace
it's just going to give you an idea of
how it can work in your program and
maybe from this example you can adapt
and use it in your own uses when you
feel like you might need it so I'm going
to get rid of this code here and we're
going to start from the beginning so the
first thing we want to do is create our
form so let's start creating that we're
going to use a method of post and the
action is going to be to the index dot
PHP again so we're submitting this form
back to index dot PHP now let's refresh
the page we've got nothing on the page
at the moment so what we want to do now
is create a text area in which users can
enter a string of data so let's create a
text area and end that there and what we
also want to do is give it a name and in
this case I'm going to call it text I'm
going to just add rows and calls this is
rows and columns just to make it a bit
larger than it is by default now we want
to break down a couple of times and we
want to say search for we break down
again we use an input type of text so by
now you should be comfortable with HTML
forms and how they work and how they
submit so I'm not going to be talking
about that too much an input type of
text and the name of this is going to be
search for now we can break down a
couple more lines and say replace with
so we're just simply setting up how our
form is can look so the input type in
this case is going to be text again text
again and the name is going to be
replace with so we can break there as
well now we want to put a submit button
so I'm going to say input type equals
submit and the value is going to be find
and replace
so let's go back to our our page and
refresh to see what we've got let's
cancel down just submit your elegant
okay so we've got the forum where we can
now type data in here we can search for
a string in here and the roof we can
replace it with a string so all of this
is string data so it's pretty easy to
work with now let's start validating our
form before we allow these functions
that we've discussed to take place so
inside PHP we're going to use to
networking your nested if statement
first of all we want to check if the
form has been submitted that's very
important we don't start processing data
at the top of our page unless the user
has actually clicked submit button and
these are present