Beginner PHP Tutorial - 51 - String Functions: Replacing Predefined Part of a String Video Lecture | PHP for Absolute Beginners: From Novice to PHP Master - Web Development

hi this is Alex from PHP academy' de org
and this is another PHP video tutorial
for the New Boston now in this tutorial
I'm going to be talking about the STR
replace function now let's have a look
at what this looks like it's STR
underscore replace he probably already
works out what it does
if not I'll talk to you a bit about that
the STR replaced typically takes three
arguments these are the required
arguments the first one is a string that
you want to look into the second is what
you want to replace a specific word with
and the last is the words that you'd
like to replace and know in actual fact
it's the other way round for the string
it's the words that you want to look for
so looking for the words here what you
want to replace and the last argument is
the string that you want to look in so
let's create an example of this we'll
just get rid of this function here I'm
going to create a string up here and I'm
going to make this equal to this is an
example and this is a string and is an
example okay so what we first of all
need to do is create a new variable you
can echo out the function in itself but
it's always good practice to create a
new variable so I'm going to say string
or no I'm going to create new string
equals STR replace and then inside here
we can start to put in our parameter out
our arguments so the first one is going
to be the words the the word that you
want to replace so I'm going to replace
the word is inside of this now the next
argument is what you want to replace it
with and I'm just going to replace it
with nothing then the last is where
you're looking so we're looking inside
this string variable here which is equal
to this value here
so what we're doing is in this function
we're looking through the whole string
and we're removing the word is because
we're replacing the word is with nothing
so we'll be removing this we'll be
removing this and we'll also be would be
removing this so let's have a look and
we'll come down here and echo out new
string let's tidy this up of it
okay so let's refresh and you can see
that we've removed the is from here
we've removed that is after that and
we've removed that is before the after
the and and we've fully and so what
happens if we want to replace a lot of
words so maybe we'll want to replace is
with something and string with something
and maybe even an example with something
now
you could come down and copy and paste
this and say oh sorry didn't mean to
leave that and we could say we want to
replace string with nothing as well and
then when we refresh you can see that
that goes as well but you can see what's
happened the ears have come back so what
happened what's going on here is the we
is a it's not a great way of actually we
could change this here to new string and
refresh so that's got rid of both of
them so we're just using the the new
string before however you can see that
this is a really really horrible not
very nice way of doing things it's going
to be slower and it's just not going to
look right so there's a simple solution
if you've already looked at arrays
you'll know what arrays are how they
work and what the uses are but this is a
really really useful way to replace many
so we're gonna create a variable good
find
and we're going to make this an array
now inside here we're going to create a
few variables in the array of a few
values of this array that we want to
replace so I'm going to choose three I'm
going to choose is string an example so
I want all these words in here
to be taken out of here or replaced with
something else so what am I going to put
in this value here we've already
selected the value is but simply I could
just put find in there and what this
function is automatically going to do is
it's going to look through each one of
these and find each one and similar
taneous ly replace them with what you
specify here so let's say I want to just
replace is with nothing string with
nothing an example with nothing this
function is now ready to work so let's
refresh and see what happens you can see
that that's deleted all three of the
words so now what happens when we want
to replace is with something but we want
to play string an example or just string
or just example with something else well
it's exactly the same concept we can
just create a new variable called
replace and we can put the values that
correspond to each one so I want to
replace is with is in capitals string
with stringing capitals and I want to
get rid of example so now what we can do
is just simply put this replace in here
and now we're all set up with both
arrays with the corresponding values
that are going to be replaced so let's
refresh and you can see that it's
capitalized that is is in the sentence
it's capitalized string and it's removed
the word example so it's a really
flexible way of doing things and it's
obviously better to use an array now why
is this function useful and why would
you use it and the example I always give
is that you may have a select few words
that you don't want to appear in maybe
some public posts on your website and
the example and a good example for this
is using a bad word filter or a
swearword filter so we could have say a
list of obscenities in a text document
and we might want to read these in on a
line-by-line basis we automatically then
if we use the file function we read in a
text file with a line by line basis and
they automatically put into an array so
then you can automatically replace a or
you can find within a certain string and
you can automatically
place an array created by different
functions so this is a really really
useful function in PHP that you'll
probably come across at some point
otherwise for now practice with it if
you've already watched my tutorial on
opening files and opening up lines of
files as an array then try and
incorporate this into it and play around
with it and see what you can come up
with and even down here you could try
and add some user input or something
that you know a user can input a certain
amount of text and then we can delete
obscenities or star out obscenities
corresponding to each value