Multiple if conditions...

joshd963

Hello chaps... ive got a little question regarding if statements.

What i want to do is, explode a string... and then depending on what the second bit of the string is, do a certain action so like...

$var = 'picture.jpg';
$break = explode('.', $var);

and then..

if($break[1] == 'jpg') {
//DO THIS
}
if($break[1] == 'png') {
// DO THIS
}
if($break[1] == 'doc OR docx') {
// DO THIS
}

etc... any ideas guys? Much appreciated..

paulnaj

if($break[1] == 'jpg') {
//DO THIS
}
if($break[1] == 'png') {
// DO THIS
}
if($break[1] == 'doc' || $break[1] == 'docx') {
// DO THIS
}

bradgrafelman

Also note that your logic above could easily be fooled, e.g. what happens if a file is named my_virus.jpg.exe?

joshd963

paulnaj;10965293 wrote:

if($break[1] == 'jpg') {
//DO THIS
}
if($break[1] == 'png') {
// DO THIS
}
if($break[1] == 'doc' || $break[1] == 'docx') {
// DO THIS
}

HI there, thank you for your response. i have changed yours a little and incorporated elseif instead of if so it only executes one condition... however i would like a condition whereby if it is none of these condiitons it will say 'file type invalid' or something like that. i tried an 'else' on the end but this didnt work.
my code:

<?php 
$name = 'picture.doca';
$break = explode('.', $name);
echo $break[0], '.', $break[1];
echo '<br><br>';

if($break[1] == 'jpg') {
echo 'A JPG';
}
elseif ($break[1] == 'png') {
echo 'A PNG';
}
elseif ($break[1] == 'doc' || 'docx') {
echo 'A DOC OR DOCX';
}
else {
echo 'FILE NOT RECOGNISED';
}
?>

bradgrafelman;10965295 wrote:
Also note that your logic above could easily be fooled, e.g. what happens if a file is named my_virus.jpg.exe?

Hello there, yeah its pretty basic, and im not sure how to fix that, however it will only be used within a local intranet for sharing excel documents etcetera and so security is not much of an issue
Regards
Josh

bradgrafelman

joshd963;10965296 wrote:
im not sure how to fix that, however ... security is not much of an issue

That last bit there is the perfect mindset/recipe for disaster. 😉 You should always consider security implications even in situations where you don't think it's necessary.

As for how to fix it, it's simple - use [man]pathinfo/man instead (e.g. with the PATHINFO_EXTENSION flag).

paulnaj

Nearly ... change

elseif ($break[1] == 'doc' || 'docx') {

elseif ($break[1] == 'doc' || $break[1] == 'docx') {

paulnaj

Brad is of course correct to suggest using pathinfo() .

Having said that, a simple trick for exploding and plucking the last element of the resulting array is to use array_pop(). In your case, you could use...

$ext = array_pop(explode('.', $name));

Just a little trick. 😉

joshd963

bradgrafelman;10965299 wrote:
That last bit there is the perfect mindset/recipe for disaster. 😉 You should always consider security implications even in situations where you don't think it's necessary.

As for how to fix it, it's simple - use [man]pathinfo/man instead (e.g. with the PATHINFO_EXTENSION flag).

cheers geeza. am i on the naughty step? 😃:o

paulnaj;10965300 wrote:
Nearly ... change
elseif ($break[1] == 'doc' || 'docx') { 
to
elseif ($break[1] == 'doc' || $break[1] == 'docx') { 

legend!!! :-)

joshd963

<?php 
$name = 'picture.doca';
$break = pathinfo($name);
echo $break['filename'], '.', $break['extension'];
echo '<br><br>';

if($break['extension'] == 'jpg') {
echo 'A JPG';
}
elseif ($break['extension'] == 'png') {
echo 'A PNG';
}
elseif ($break['extension'] == 'doc' || $break['extension'] == 'docx') {
echo 'A DOC OR DOCX';
}
else {
echo 'FILE NOT RECOGNISED';
}
?>

This is what i have now. Its fully functioning. For anyone thats interested.
Cheers

jgetner

Are you sure you got this fully working? As i found a parser error.

echo $break['filename'], '.', $break['extension'];  // your original code with parser error.

echo $break['filename'] .'-'. $break['extension']; // new code.

for the record comma's or not used for escaping that is what a period does.

NogDog

jgetner;10965304 wrote:
Are you sure you got this fully working? As i found a parser error.
echo $break['filename'], '.', $break['extension'];  // your original code with parser error.

echo $break['filename'] .'-'. $break['extension']; // new code.
for the record comma's or not used for escaping that is what a period does.

Actually, there is no parse error. [man]Echo[/man] specifically allows for the use of the comma to separate expressions to be echoed, as long as they are not within parens:

// legal:
echo $foo, $bar;
// illegal:
echo ($foo, $bar);

bradgrafelman

Additionally...

jgetner;10965304 wrote:
for the record comma's or not used for escaping that is what a period does.

Neither are used for "escaping" - the period is the "concatenation" operator.

jgetner

Huh thanks nogdog did not know that.... learning something new.

NogDog

jgetner;10965333 wrote:
Huh thanks nogdog did not know that.... learning something new.

I don't think I've ever used it that way in PHP, but I remembered seeing it somewhere before. I think Perl does the same thing, if memory serves? (It's been several years now since I did anything at all with Perl.)

bradgrafelman

NogDog;10965339 wrote:
(It's been several years now since I did anything at all with Perl.)

Heh... the last thing I used Perl for was to scare someone into realizing how much easier it would be to learn PHP... :p

cretaceous

I would have thought this was the perfect place for a switch statement


switch $break[1] {
case 'jpg' : 
    echo 'A JPG';
    break;

case 'png' : 
    echo 'A PNG';
    break;

case  'doc' :
case 'docx' :
    echo 'A DOC OR DOCX';
    break;

default:
     echo 'FILE NOT RECOGNISED';

}

(the "break;" part is critical to stop the code once it finds a match)

bradgrafelman

cretaceous;10965427 wrote:
I would have thought this was the perfect place for a switch statement

It's a matter of preference, really. For example, I hate the way switch() structures look in code, so I never use them.

cretaceous

for long 'if else' patterns and a default I think they are models of clarity!
I agree - they are certainly not good for all occasions

NogDog

Or get all OOP about it and use sub-classes and a factory or decorator pattern to implement them at run-time. 🙂

joshd963

nice code cretaceous 🙂 i havent seen that before