print_r blank space in output - php

Question

I'm working with arrays in PHP and I have noticed strange output with some of the values having an extra line of blank space as shown below.
Array
(
[0] => Array
(
[token] => data
[tag] => data
)
[1] => Array
(
[token] => data
[tag] => data
)
etc.
This alternates with every other element having the extra blank space until element 5. Then they all look like [1] until they reach element [9] which has the strange whitespace line again.
Some data is duplicate too yet this doesn't effect whether the two elements will have the same whitespace issue.
Can this cause me problems or does it show an issue within my code? Why do some elements have this additional whitespace?
EDIT:
I did a var dump, and I have identified that some of the tags have a newline after them.
e.g.
"tagexample
"
rather than
"tagexample"
This is confusing however because as I said, a lot of the tags are duplicates and used for multiple tokens and it seems random which is affected.
EDIT2:
I did var export and that shows the same result as above, i.e.
'tag' => 'data
',

Answer 1

try this:
$arr = array(
array( 'token' => 'stuff 1',
'tag' => 'data 1
', ),
array( 'token' => 'stuff 2',
'tag' => 'data 2
', ),
array( 'token' => 'stuff 3',
'tag' => 'data 3
', ),
);
print "<pre>";
print_r($arr);
foreach($arr as $index => $sub) {
$arr[$index] = array_map('trim',$sub);
}
print "\n\n----------------------------------------------------\n\n";
print_r($arr);
/*
Array
(
[0] => Array
(
[token] => stuff 1
[tag] => data 1
)
[1] => Array
(
[token] => stuff 2
[tag] => data 2
)
[2] => Array
(
[token] => stuff 3
[tag] => data 3
)
)
----------------------------------------------------
Array
(
[0] => Array
(
[token] => stuff 1
[tag] => data 1
)
[1] => Array
(
[token] => stuff 2
[tag] => data 2
)
[2] => Array
(
[token] => stuff 3
[tag] => data 3
)
)
*/
could also be written as:
function trim_the_sub_array($sub) {
return array_map('trim',$sub);
}
$arr = array_map('trim_the_sub_array',$arr);

Answer 2

print_r() is a debugging function (http://php.net/print_r) and you need not worry about the whitespaces if you are using it for debugging. If you use it for output (say for a log), var_export() (http://php.net/var_export) would be a better choice since it prints actual PHP code for defining the array in question.
As you have mentioned, if some data is duplicated and if it's not the intended behavior then probably there is an issue in your code. You will be able figure that out by focusing on where the array is populated.