Single Quotes & Concatenation Video Lecture | PHP for beginners - Software Development

hello YouTube welcome to the seventh
tutorial and the PHP tutorial series and
this is going to be quite a confusing
concept to the score support hopefully
we can get we can get over it we can get
around it and this will work through all
the newbie spot you know in my tutorial
well I should wear shoot out the output
text I use double quotes and I did say
that we can use single quotes with
concatenation and that's pretty much I'm
going to be discussing in this video so
first of all what is the difference
between double and single quotes well
let's just write a quick a little script
that will output text to the browser the
first one will be echo with double
quotes hello world and the second one
will echo hello world with single quotes
and we'll save that as string stop PHP
okay so if we go to string stop PHP
you'll notice that they are exactly the
same and there's no break there so I'll
just put a P in HTML line break right
there and you'll see they're exactly the
same thing but the difference between
these is I'll just show you that right
now through a variable I'll declare a
variable called name
I'll just and where it's going to be
called and we'll sign that with the
value of world and Enda and you'll know
from the variables tutorial you know to
include a variable in a string out put
it you'll just type the word and word
but if we do that down here we'll get a
different result and if I save this and
show you that you'll notice that's the
first one and I apologize I should put a
line break in there to make it easier to
show you'll notice that at the face line
outputs the variable on the second one
doesn't and I'm just going to explain
the difference between a double quote
and a single quote now when you have a
string with a double quote that is
telling PHP to pass the whole string and
find the variable so if you have a
variable it's going to say okay
we'll start with double quotes now
please PHP look through here and take
the variable and convert it to the
actual value which is well but when you
have single quotes you're just skipping
that process and outputting the entire
string as a string so the difference is
and when you want to have a variable
with a single quote you need to
concatenate it and I'm not sure I should
I'll just explain first of all what why
it does this when you have double quotes
PHP will pass it further variable and
that means that it's quite it takes
longer to execute this script and other
only outputting to words it's quite
minimal is only one variable so it
doesn't take long but if you have
thousands and thousands of words there
will be quite a small in performance
difference that you notice when
outputting the variables so how can you
get around this well if you want to
output a single quotes and you want to
use a variable you can concatenate it so
let's just go back here and we're going
to put this in single quotes world okay
okay so if you want to echo out that you
know we want to say hello world what you
want to use single quotes you can do it
like this let go and as you'll start off
with hello then put a space and now
we're going to end string and what we
can do is actually join a variable on
with a string by concatenation and you
do that using a full-stop
so just our full stop and then after the
full stop you will have the variable
name which is world and then we'll have
another full start and then you know we
can actually have more text after this
so you can just have a break and then
end it and have a semicolon we save that
you'll see that you've used a single
quote and we've actually concatenated a
variable onto it so if we wanted to do
this with double quotes you know we
would just do echo hello world and you
look at that it looks a lot easier to do
the double quotes doesn't it and whoops
we save the reload it same thing
but the difference is with performance
but also what I'm going to discuss now
is how to echo out HTML so let's just go
back and let's just use double quotes
and we're going to change this going to
create a variable called Google okay and
actually won't use available right now
we'll just echo out something to prove a
point so if we echo out and in double
quotes are going to echo out a link now
if you don't know how to use a link in
HTML it's just it goes like this you
open brackets a href equals and in
double quotations you will put Google
comm and end the link you'll end it and
then after this will be the anchor text
which is what is shown as the text for
the link and then we'll end it with with
that so you guys should know basically
how to output a link if you're learning
PHP if you don't you can google it
well that will just output the link
Google or will it so we save this and
you'll see we have a parse error and
that's because if we look at this like
we look at this as a normal person we
think okay we open it here we put the
link and we end there but let's look at
this from a PHP point of view we open up
the double quotes and let me type a href
equals but then here when we're adding
the link we're actually closing a string
so what we can do here is there's two
options that we have and the easiest
option is to just use a single quote so
let's close this and we're going to do
echo single quotes and we'll just put a
href HTF whoops equals google.com and
then we can just type Google and close
it and which style semicolon right there
oops what am i doing and now you can see
that I'll link actually works so what I
do is when I'm using HTML I will use a
single quote and that's because it's
much easier to write the HTML because
you don't have to escape as many
characters and explain that one moment
but if I'm you know I'm actually quite
lazy so if I'm just doing you know
outputting some text with a variable I
will just use double quotes so I'm just
going to echo different just for example
I'm just going to say you know my name
is a name unless just imagine that this
name variable has been declared with the
value of Chris I'll just do that so you
know let's say if you want to use a
variable in HTML let's just import link
as the variable I'm going to assign that
to the value of Google and then inside
here where it says Google we can just
concatenate the variable in here we'll
end the full-stop
and then we'll just put the variable
link another . and we'll start up the
string again okay so let's let's see
them go back to single quotes and let's
say we have a variable now let's say we
actually want to echo out in a string
but it has an apostrophe and so hello
it's a nice day to code PHP and all
we're saying here is you open it and you
say hello it's a nice day to call PHP
and we'll close it and then we'll have a
semicolon and we'll save that and you'll
notice there's a parse error and it goes
back to the same problem as before
PHP thinks that we've ended the code
here with the apostrophe when an actual
fact we wanted to carry on so all we
need to do here is do a back slash and
this is known as an escape and what this
does is say this tells PHP okay the the
value after this backslash M is don't
regard this as a PHP method just regard
this as a normal string so if we save
this reload it we can see that his it
has way and there's no parse error and
also if you want to do a back slash a
little back slash you just do like and
we can let's just type out we can use
double backslash single quotes
but if we reload the and actually that
works I'm not sure I actually thought
that you had to do a double backslash -
actually I'll put a backslash book in
PHP five it must have updated or I must
just be your membrane wrong so actually
I'll just use double backslash is in
case if depending on it might be an
older version of PHP installed in
webserver so you know that works as well
so that was just this tutorial and let's
just go over what we've learned in this
tutorial in for starters double quotes
allow variables to be used inside of the
string without concatenate them so you
can just write a string echo out with
string and then use a variable with that
but it is slower to pass a variable with
double string because you have to you're
telling PHP there's a variable in there
so it has to pass through and get out
all the variables and with a single
quote it's actually faster to execute on
a server but you need to concatenate the
variables so let's just let's just say
it's faster to type out with double
quotes but it's faster for the server to
executors with single quotes and to
write HTML it's more convenient to use
single quotes because double quotes are
use quite often in pn HTML so it will be
difficult and quite messy to escape all
of the HTML double quotes um yeah that's
what we've learned in this tutorial so
it's actually quite pointless or not not
pointless that's not what I was looking
for it's actually not relevant right now
to you because you're not going to be
right now lots massive strings so it
doesn't really matter about passing out
variables and double quotations so what
I do is when I'm just when I'm writing
out echoing out some strings and has a
variable in it but I'm not using HTML
I'll just use double quotes but if I'm
using HTML I'll use single quotes and
then I'll concatenate the variables so
yep that's pretty much the summary of
this tutorial so I hope
you guys learned a lot from this if you
didn't then you know watch over it again
or it doesn't actually matter that much
but please like the video and subscribe
to the channel and if you have any
questions on this just leave a comment
and yeah enjoy the next tutorial