If statement trouble

I'm having trouble with this if statement:

if($line[$c]=$ignore
{
$num--;
}


$ignore is defined as the string "ig"

$line is an array containing 5 items, some of which may be "ig"

$num starts out as a number representing the number of values in $line


The if statement you see above is nested inside a small for loop that
simply runs throught the process 5 times, and goes through the array
$line. At each point it is SUPPOSED to check and see if the current
value of $line at that particular slot ($c) is equal to "ig". If so,
then it decrements $num by 1.

My problem is it doesn't seem to care whether or not $line[$c] equal
"ig" or not. It's just decrementing $num all willy nilly.

AceX

On Feb 25, 3:06 pm, AceX <AceIncorpora...@gmail.com> wrote:
> I'm having trouble with this if statement:
>
> if($line[$c]=$ignore
> {
> $num--;
>
> }
>
> $ignore is defined as the string "ig"
>
> $line is an array containing 5 items, some of which may be "ig"
>
> $num starts out as a number representing the number of values in $line
>
> The if statement you see above is nested inside a small for loop that
> simply runs throught the process 5 times, and goes through the array
> $line. At each point it is SUPPOSED to check and see if the current
> value of $line at that particular slot ($c) is equal to "ig". If so,
> then it decrements $num by 1.
>
> My problem is it doesn't seem to care whether or not $line[$c] equal
> "ig" or not. It's just decrementing $num all willy nilly.
>
> AceX

You need == in the if test instead of just =.

= is the assignment operator. It assigns a value to a variable. ==
is a logical test for equality.

..oO(AceX)

>I'm having trouble with this if statement:
>
>if($line[$c]=$ignore
>{
> $num--;
>}
>
>
>$ignore is defined as the string "ig"
>
>$line is an array containing 5 items, some of which may be "ig"
>
>$num starts out as a number representing the number of values in $line
>
>
>The if statement you see above is nested inside a small for loop that
>simply runs throught the process 5 times, and goes through the array
>$line. At each point it is SUPPOSED to check and see if the current
>value of $line at that particular slot ($c) is equal to "ig". If so,
>then it decrements $num by 1.
>
>My problem is it doesn't seem to care whether or not $line[$c] equal
>"ig" or not. It's just decrementing $num all willy nilly.

= != ==

Your code above is an assigment, not a comparison.

Micha

you are assigning $ignore to $line[$c], so all 5 items become 'ig',
'ig' within if always leads to successful 'if' execution,
use == operator instead to compare.

if there is only one statement within 'if' then curly brackets are not
necessary ( also for 'for', 'while',.....).

use

if($line[$c]==$ignore) $num--;

also there is another operator ===, to know about ===, see php
documentation.

AceX wrote:
> I'm having trouble with this if statement:
>
> if($line[$c]=$ignore
> {
> $num--;
> }
>
>
> $ignore is defined as the string "ig"
>
> $line is an array containing 5 items, some of which may be "ig"
>
> $num starts out as a number representing the number of values in $line

In addition to using an assignment operator (=) instead of comparison
(==), you are also missing a close parenthesis:
if($line[$c]=$ignore
should be
if($line[$c]==$ignore)

And, yes, the brackets are not NEEDED if you have only one statement,
but they don't hurt.

On Feb 25, 5:21*pm, Tony <nos...@example.com> wrote:
> AceX wrote:
> > I'm having trouble with this if statement:
>
> > if($line[$c]=$ignore
> > {
> > * * *$num--;
> > }
>
> > $ignore is defined as the string "ig"
>
> > $line is an array containing 5 items, some of which may be "ig"
>
> > $num starts out as a number representing the number of values in $line
>
> In addition to using an assignment operator (=) instead of comparison
> (==), you are also missing a close parenthesis:
> if($line[$c]=$ignore
> should be
> if($line[$c]==$ignore)
>
> And, yes, the brackets are not NEEDED if you have only one statement,
> but they don't hurt.

Thank you all. I don't know if anyone else has this problem, but
sometimes I just have brain lapses. I appreciate all the help guys
(and gals?)

AceX wrote:
> On Feb 25, 5:21 pm, Tony <nos...@example.com> wrote:
>> AceX wrote:
>>> I'm having trouble with this if statement:
>>> if($line[$c]=$ignore
>>> {
>>> $num--;
>>> }
>>> $ignore is defined as the string "ig"
>>> $line is an array containing 5 items, some of which may be "ig"
>>> $num starts out as a number representing the number of values in $line
>> In addition to using an assignment operator (=) instead of comparison
>> (==), you are also missing a close parenthesis:
>> if($line[$c]=$ignore
>> should be
>> if($line[$c]==$ignore)
>>
>> And, yes, the brackets are not NEEDED if you have only one statement,
>> but they don't hurt.
>
> Thank you all. I don't know if anyone else has this problem, but
> sometimes I just have brain lapses. I appreciate all the help guys
> (and gals?)
>

Ace,

I don't know how many times I've done that - stretching all the way back
to the mid 80's when I was writing C code :-)

Also C++, Java, PHP...

It's also a common error in many of my classes - students will look and
look at the code and don't see what the problem is. When I point it out
in about 2 seconds, they feel embarrassed - until I tell them I spotted
it so quickly just because I HAVE made that mistake so many times. :-)


--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================

In article <iZednQvBrNDbgFnanZ2dnUVZ_oqhnZ2d@comcast.com>,
Jerry Stuckle <jstucklex@attglobal.net> wrote:

> AceX wrote:
> > On Feb 25, 5:21 pm, Tony <nos...@example.com> wrote:
> >> AceX wrote:
> >>> I'm having trouble with this if statement:
> >>> if($line[$c]=$ignore
> >>> {
> >>> $num--;
> >>> }
> >>> $ignore is defined as the string "ig"
> >>> $line is an array containing 5 items, some of which may be "ig"
> >>> $num starts out as a number representing the number of values in $line
> >> In addition to using an assignment operator (=) instead of comparison
> >> (==), you are also missing a close parenthesis:
> >> if($line[$c]=$ignore
> >> should be
> >> if($line[$c]==$ignore)
> >>
> >> And, yes, the brackets are not NEEDED if you have only one statement,
> >> but they don't hurt.
> >
> > Thank you all. I don't know if anyone else has this problem, but
> > sometimes I just have brain lapses. I appreciate all the help guys
> > (and gals?)
> >
>
> Ace,
>
> I don't know how many times I've done that - stretching all the way back
> to the mid 80's when I was writing C code :-)
>
> Also C++, Java, PHP...
>
> It's also a common error in many of my classes - students will look and
> look at the code and don't see what the problem is. When I point it out
> in about 2 seconds, they feel embarrassed - until I tell them I spotted
> it so quickly just because I HAVE made that mistake so many times. :-)

It's not only that. A certain blindness creeps in and one can overlook a
mistake a number of times even though you know there's one there. That's
when it's often much quicker to have a*fresh* set of eyes looking.

Jerry Stuckle wrote:

> It's also a common error in many of my classes - students will look and
> look at the code and don't see what the problem is. When I point it out
> in about 2 seconds, they feel embarrassed - until I tell them I spotted
> it so quickly just because I HAVE made that mistake so many times. :-)

One handy trick to help yourself avoid this problem is that whenever one
of the sides in your comparison is a constant or an expression, place that
side on the left.

For example, instead of one of these:

if ($foo == 0) { /* ... */ }
while ($bar == abs($i)) { /* ... */ }

write:

if (0 == $foo) { /* ... */ }
while (abs($i) == $bar) { /* ... */ }

That way, if you accidentally leave out an equals sign you get:

if (0 = $foo) { /* ... */ }
while (abs($i) = $bar) { /* ... */ }

and you'll get a nice compile-time error telling you the line number.

--
Toby A Inkster BSc (Hons) ARCS
[Geek of HTML/SQL/Perl/PHP/Python/Apache/Linux]
[OS: Linux 2.6.17.14-mm-desktop-9mdvsmp, up 27 days, 22:18.]

Bottled Water
http://tobyinkster.co.uk/blog/2008/02/18/bottled-water/

Jerry Stuckle wrote:
> AceX wrote:
>>
>> Thank you all. I don't know if anyone else has this problem, but
>> sometimes I just have brain lapses. I appreciate all the help guys
>> (and gals?)
>>
>
> Ace,
>
> I don't know how many times I've done that - stretching all the way back
> to the mid 80's when I was writing C code :-)
>
> Also C++, Java, PHP...
>
> It's also a common error in many of my classes - students will look and
> look at the code and don't see what the problem is. When I point it out
> in about 2 seconds, they feel embarrassed - until I tell them I spotted
> it so quickly just because I HAVE made that mistake so many times. :-)

I don't know how often I've simply asked someone to take a look at some
code - because sometimes you get too close to the code, and you just
don't see those sort of simple errors. Someone else's fresh perspective
is all it takes.