Need help to understand code piece.

[wadej30084]

Hi there, i have an code
 

<?php
$a = [
  0 => 10,
];
$i = 0;

$a[$i++] = $i;

and question "Explain what the problem is and what you could do to fix it"

I read this and I totally not understand what it for and how it use and what problem hidden here.
 

Please help!
 

[mconte]

ok, so $a[0] will equal 1

what do you want it to do?

Edited February 11, 2020 by mconte

[wadej30084]

Just now, mconte said:

ok, so $a[0] will equal 1

It's all about using ++$i instead $i++ or what, because I ran this code and stuck on understand what wants from me?

[wadej30084]

I have an question for it
"Explain what the problem is and what you could do to fix it"
and nothing more, that's why I'm stacked.

[mconte]

sure, if you did $a[++$i], it would increment $i first and set a new index $a[1] = 1

[wadej30084]

17 minutes ago, mconte said:

sure, if you did $a[++$i], it would increment $i first and set a new index $a[1] = 1

thanks for advice!

[requinix]

20 minutes ago, mconte said:

sure, if you did $a[++$i], it would increment $i first and set a new index $a[1] = 1

Not necessarily. PHP makes no promise that the $i on the right happens before or after the ++$i on the left.

[mconte]

19 minutes ago, requinix said:

Not necessarily. PHP makes no promise that the $i on the right happens before or after the ++$i on the left.

https://www.php.net/manual/en/language.operators.increment.php

[requinix]

9 minutes ago, mconte said:

https://www.php.net/manual/en/language.operators.increment.php

Yes, that describes how one pre-increment operation works on a variable. That page does not explain how one or more pre- or post-increment operators on the same variable work when in the same expression.

The concept is called a sequence point. Look into it: most everything you'll find will talk about C/C++, but it applies to PHP as well.

[ginerjm]

I personally can not see how I would ever write a block of code that looks like this!! What is that supposed to accomplish?   Never mind - I don't want to know.

 

[requinix]

33 minutes ago, ginerjm said:

I personally can not see how I would ever write a block of code that looks like this!! What is that supposed to accomplish?   Never mind - I don't want to know.

Obviously it isn't real code someone would write. Not all of it. But that last line, that's something one could reasonably write in some circumstance.

[wadej30084]

Ok, I see you like it, I have another one.
Same situation have code piece:
 

function getAdminName()
{
    global $admin;
    return ($admin['gender'] ? 'Mr' : 'Mrs').' '.$admin['fullname'];
}

and simple question:

"This code isn't ideal. Explain what the problem is and what you could do to fix it"

it's all, please help! Today I have no idea what's wrong except this is creepy realization and I do this in totally another way.

P.S. ginerjm asking what is it, this is a part of practical tasks of technical php test and I trying do my best to solve it, but even if I fail on exam I need to understand what's it about.

All this about: "You need to think globally, we need to see how you think."
And like Ross Geller's little hand monkey, but in my head, beating in cymbals plates, with deep understanding of this code problem eyes look.

Thanks for help!

[maxxd]

The portion of your last code bit in parenthesis is called a ternary operator. I recommend reading up on it as it's something you'll see often if my experience is at all typical.

[wadej30084]

31 minutes ago, maxxd said:

The portion of your last code bit in parenthesis is called a ternary operator. I recommend reading up on it as it's something you'll see often if my experience is at all typical.

Thanks, for reply. I know what is ternary operator, also I know about latest deprecated features about this operator in 7.4 version, but i don't see here any problem with it, any complex use like 1 ? 2 : 3 ? 4 : 5; , the problem is what i don't understand what I'm must looking for in this piece of code. Any advice?

[requinix]

1 hour ago, wadej30084 said:

but i don't see here any problem with it, any complex use like 1 ? 2 : 3 ? 4 : 5;

But here's the question: what is that expression going to evaluate to? 2 or 4?

1 hour ago, wadej30084 said:

the problem is what i don't understand what I'm must looking for in this piece of code. Any advice?

The problem is the last line. It uses $i++ and $i in one statement, and that's a no-no. Did you see when I mentioned sequence points earlier? Look into it.

[maxxd]

2 hours ago, wadej30084 said:

1 ? 2 : 3 ? 4 : 5;

In the name of all that you find holy, please don't do that.

[requinix]

1 hour ago, maxxd said:

In the name of all that you find holy, please don't do that.

Fortunately PHP 7.4 won't let it happen.

[wadej30084]

Hi, maybe I'm saying something wrong, but I'm talking about this piece of code, another from first post:

function getAdminName()
{
    global $admin;
    return ($admin['gender'] ? 'Mr' : 'Mrs').' '.$admin['fullname'];
}

 

Help is needed with it, be answering on the question:
"This code isn't ideal. Explain what the problem is and what you could do to fix it"

[Phi11W]

59 minutes ago, wadej30084 said:

I'm talking about this piece of code

the convention around here is "New question, new thread". 
That allows for short, direct answer to short, direct questions instead of long, rambling threads where all the "Goodness" gets lost. 

 

1 hour ago, wadej30084 said:

function getAdminName() 
{ 
   global $admin;
   return ( $admin['gender'] ? 'Mr' : 'Mrs') . ' ' . $admin['fullname'] ;
}

Some comments on the above: 

• the use of "global" breaks encapsulation, requiring the environment "outside" the function to provide the variable. 
  It is better to pass the data as an argument to the function. 
• What value does admin['gender'] have? 
  Any value passed that resolves to true will cause the ternary operator to return "Mr" and everything else will return "Mrs". 
• The code makes no attempt to ensure that the array indexes used actually exist; this may or may not be an issue.  
• What if the individual is female and not married? 
  They might object to being called "Mrs". 
• What if the individual is not gender-identifying? 
  They would object most strongly to be referred to by either of the terms used here. 

Marital status and/or gender are both Personal Data and should be stored in the User's "record" (whatever form that takes) so that it can be managed by/on behalf of the User and changed over time.  

Regards, 
   Phill  W.

 

[wadej30084]

4 minutes ago, Phi11W said:

the convention around here is "New question, new thread". 
That allows for short, direct answer to short, direct questions instead of long, rambling threads where all the "Goodness" gets lost. 

 

Some comments on the above: 

• the use of "global" breaks encapsulation, requiring the environment "outside" the function to provide the variable. 
  It is better to pass the data as an argument to the function. 
• What value does admin['gender'] have? 
  Any value passed that resolves to true will cause the ternary operator to return "Mr" and everything else will return "Mrs". 
• The code makes no attempt to ensure that the array indexes used actually exist; this may or may not be an issue.  
• What if the individual is female and not married? 
  They might object to being called "Mrs". 
• What if the individual is not gender-identifying? 
  They would object most strongly to be referred to by either of the terms used here. 

Marital status and/or gender are both Personal Data and should be stored in the User's "record" (whatever form that takes) so that it can be managed by/on behalf of the User and changed over time.  

Regards, 
   Phill  W.

 

Wow, this a big explanation, many thanks Phill!
P.S. I keep in mind about new thread.

[Barand]

… or their correct salutation is Dr,  or some other title (eg Prof.) that is not gender-related

[gizmola]

Phi11w provided an excellent and thorough analysis.  In particular consider this data for $admin:

 

<?php

$admin = ['fullname' => 'Sally Smith', 'gender' => 'F'];

function getAdminName() 
{ 
   global $admin;
   return ( $admin['gender'] ? 'Mr' : 'Mrs') . ' ' . $admin['fullname'] ;
}

echo getAdminName();

Do you get what you would expect for a gender 'F' person named 'Sally Smith'?  While all of Phi11w's points are valid, I think this is the main thrust of the issue.  Even without knowing the scheme to be used, it is unlikely that gender would be a boolean value.

Another issue being glossed over, is that 'Mrs' has the connotation of marriage, as well as Barand's point about 'Dr' and other sultations, but that makes things more complicated, and I don't think that was factored into the question, because the existing code has an obvious data typing issue.

So an improved function (assuming php7):

 

<?php

$admin1 = ['fullname' => 'Sally Smith', 'gender' => 'F'];
$admin2 = ['fullname' => 'Randy Jones', 'gender' => 'm'];
$admin3 = ['fullname' => 'Pat Samuels'];

function getAdminName($admin) 
{ 
   $admin['fullname'] = trim($admin['fullname']) ?? 'unknown';   
   $admin['gender'] = $admin['gender'] ?? '';
  
   $pre = '';
   switch (strtolower($admin['gender'])) {
       case 'f':
           $pre = 'Mrs ';
           break;
       case 'm':
           $pre = 'Mr ';
           break;
        default:
            $pre = '';
   }
   return $pre . $admin['fullname'];
}

echo getAdminName($admin1) . PHP_EOL;
echo getAdminName($admin2) . PHP_EOL;
echo getAdminName($admin3) . PHP_EOL;

Quote

Output:

Mrs Sally Smith

Mr Randy Jones

Pat Samuels