Questions~

cybresophistoM

Hi guys, i have 2 questions that i hope someone will help me on. Because its killing me, i can't solve it.

1) Write a function that will convert an array of lower case strings passed by reference into an array of upper case strings

e.g function convert(&$array_strings){

         //insert code

}

I tried this:

function convert(&$array_strings)
{
$array_strings="hello this is php coding in lower case to upper case";
$higher=strtoupper($array_strings);
print("$higher");
}

2)Using regular expressions generate a function that will check if a filename stored in a string is of the correct format. The function should return a Boolean result. Any 1 upper case letter, followed by 3 lowercase letters, followed by any digit, followed by a .php or .PHP file

eg. Gone8.php

I tried this:

function regular_expressions($boolean)
{
if(preg_match("/[A-Z]{1}[a-z]{3}[0-9][.]p[Hh]p/","Gone8.php"))
{
return 1;
if ($boolean == 1)
{
print("true<br/>");
}

return false;
}

Extra: what happens if you try "Gone8.phpProblem" Does it return true or false? Can you fix the problem if there is one?" --->Can anyone explain the answer and rationale behind it to me ?

Many thanks!

laserlight

For the first problem: you are on the right track, but need to loop over the array instead.

For the second problem: think of using | instead since the requirements are "php" or "PHP".

cybresophistoM wrote:
Extra: what happens if you try "Gone8.phpProblem" Does it return true or false? Can you fix the problem if there is one?" --->Can anyone explain the answer and rationale behind it to me ?

Hint: assert the start and end of the subject string in your regular expression pattern.

cybresophistoM

hmm for question 1, what loop is necessary? while? For? if ..else?

and i do not quite understand your hint for question 3. Mind if you explain further?

hey are u from singapore? I love their laksa and char kway teow 🙂

laserlight

cybresophistoM wrote:
hmm for question 1, what loop is necessary? while? For? if ..else?

if-else statements are not loops 🙂
I would use a foreach loop, but you certainly can use other types of loops as well.

cybresophistoM wrote:
and i do not quite understand your hint for question 3. Mind if you explain further?

Unless you state otherwise, a regular expression tries to get a match, anywhere. Consequently, it could match a valid pattern embedded in some junk. To exclude these junk, you assert that the pattern should match from the start and end of the string. This way, when the junk is detected, there would be no match.

cybresophistoM wrote:
hey are u from singapore? I love their laksa and char kway teow

I am. However, I hate laksa and love char kway teow :p

cybresophistoM

hmm, i still have no idea on getting to do question 3. so ,does that mean it will return true?
Meanwhile, i don't know how, but i'll try google-ing for hints :queasy:

I've been to Vivo city before, nice place to hang out. I might probably head down to Bugis during my next vacation.

laserlight

cybresophistoM wrote:
hmm, i still have no idea on getting to do question 3. so ,does that mean it will return true?

Do question 2 first, and test to find out for yourself 🙂

cybresophistoM wrote:
Meanwhile, i don't know how, but i'll try google-ing for hints

The correct place to look is the PHP manual's entries on Regular Expressions (Perl-Compatible).

brbourdo

im not super sure why you want to run a custom function for a feature that is already provided in php. but the following function analyzes a string character by character, makes it upper case, and prints it.

function convert(&$array_strings)
{

$array_strings = "hello i want to be in capital letters";
$length = strlen($array_strings);
$charString = preg_split('//', $array_strings, -1);

for($i = 0; $i < ($length+1); $i++)
{
	if($charString[$i] == ' ')
	{
		$upperCase[$i] = " ";
	} else
	{ 
		$upperCase[$i] = strtoupper($charString[$i]);
	}
}

foreach($upperCase as $value)
{
	echo $value;
}

}

$test = convert();

laserlight

brbourdo wrote:
im not super sure why you want to run a custom function for a feature that is already provided in php.

Uh, note that cybresophistoM provided the code that was his/her attempt. The error in that code is the application of strtoupper() to the array aliased by $array_strings instead of each element of that array.

Your suggested function is very different as it pretty much ignores the $array_strings parameter, using it as if it were only an ordinary local variable, and then provides its own input (which means that it pretty much cannot be reused), but in actuality $array_strings is an in/out parameter that is an array. Furthermore, strtoupper() works on strings, not just characters, and the check for spaces is unnecessary as strtoupper() already handles spaces correctly.

brbourdo

i knew about strtoupper, which is why i was confused on why he wanted it, didnt know it properly handled spaces tho. but after re-reading i get it. i didnt mean for it to set its own variable in actual production use, i just did it that way for the example. as im sure ur fully aware, it would only be a line or two to have it accept any string passed to it.

but yea, ill pay a little more attention next time haha. yea my code is pretty much useless for what he wanted.

reading = win