building arrays

[Anon]

Newbie question:

I'm building an array in a for loop, adding values using the $A[] = $value method, where $value is a string.

when reading the resulting array it seems to be empty, or at least it's filled with "" values.

I know that $value has the correct value. If anyone can tell me what I'm doing wrong, please tell me.

Code:
for ($i = 0; $i < count($sourceA); $i++)
{
$value = $sourceA[$i];
$resultA[] = $value;
}

Thanks,

Eddie

[Anon]

May be, the problem is that you read values from your array incorrectly? If you do:
print($resultA[]);
it will print an empty string - you should define array index:
print($resultA[1]);
and it will print the first element of your array (the second, you see - arrays begin with 0 element :-))

[Anon]

o...
have u initialized the string variable?
like, $sourceA[] = "o..this is a string";
thx

your code is correct i think...

[Anon]

first, you must have value in $sourceA array like follow code

$sourceA[0]=0;
$sourceA[1]=1;
$sourceA[2]=2;
$sourceA[3]=3;
$sourceA[4]=4;
$sourceA[5]=5;

and then you can run follow code right

for ($i = 0; $i < count($sourceA); $i++)
{
$value = $sourceA[$i];
echo $value;
}

if you want save the value to $resultA, you must change the echo $value to
$resultA[$i] = $value;

that's right

yorgo

[Anon]

I'm not sure what you are doing, but I can provide you with a simpler way of traversing arrays:

Suppose you wanted to push a couple of names on a array without index. You could do something like this (you'll probably read the values from another source):

$arrFirstNames = array();

$arrFirstNames[] = "Ronnie";
$arrFirstNames[] = "Anders";
$arrFirstNames[] = "Tommy";
$arrFirstNames[] = "Per-olav";

To walk this array and print out the names,
don't use for loops, it only adds complexity.
Using the form below is easier to read and actually more visually appealing 😉

while( list( $nIndex, $sName ) = each( $arrFirstNames ) )
{
echo "[$nIndex] $sName<br>";
}

each() retreives a valuepair of a array in the form: [key][value] and list() extracts values from an array. In this case it extracts and assign the index to $nIndex and the name to $sName.

You elliminate the risk "off-by-one" error by using this approach.

Let's say you wanted to do the same with associative arrays (or whatever the name is).
Start by initialising the array:

$arrNames = array();

$arrNames[ "Ronnie" ] = "Bahlsten";
$arrNames[ "Anders" ] = "Odeskog";
$arrNames[ "Tommy" ] = "Martinsson";
$arrNames[ "Per-olav" ] = "Gramstad";

To walk the array echoing the names, use the suggested approach and do somehing like this:

while( list( $sFirstname, $sLastname ) = each( $arrNames ) )
{
echo "$sFirstname $sLastname <br>";
}

Hmm... I sounded suspiciously much like a teacher 😉
Well, hope that this helped you out a bit.

/ Ronnie