[PHP-DEV] Bug #15330 Updated: An efficient way to access the last element of an array is sorely missed
ID: 15330 Updated by: [EMAIL PROTECTED] Reported By: [EMAIL PROTECTED] Status: Bogus Bug Type: Feature/Change Request Operating System: N/A PHP Version: 4.1.1 New Comment: Yes, I am aware of end(). It certainly has a purpose and a use, but it isn't at all the same as what I was suggesting. Frankly, I never use the internal pointer features of arrays, as they were at first alien to me, and later seemed unreliable when I thought I understood them. Providing altenative methods for ding things in programming language as otherwise accomodating as PHP, seems to me, precisely in character with its philosophy. I would be more than happy to contribute these functions myself, if someone will point me in the right direction to do so. Thank you. --HaigEK Previous Comments: [2002-02-01 15:11:56] [EMAIL PROTECTED] These functions have been available for a long time and are well documented in the manual--see the previous comment. Torben [2002-02-01 14:38:56] [EMAIL PROTECTED] While there is no way to set the internal pointer (afaik) to a given element #, you can set the pointer to the first/last/next/previous item. http://se.php.net/manual/en/function.end.php end -- Set the internal pointer of an array to its last element. -- mats [2002-02-01 14:07:08] [EMAIL PROTECTED] There seems to be no easy and efficient way to access the last element of an array (assuming you don't already know the key to that element). The most concise, though not terribly efficient workaround I have discovered is... $array[array_pop(array_keys($array))] ...which first extracts all the keys of the array, then pops off the last key and uses it as an index into the array. Fairly easy to write and understand (though bulky), but horribly inefficient. Perhaps there is a place for new array_lastkey($array), array_firstkey($array), and array_element_key($array, $n) functions. The first of these functions would simply return the last key in the array (or null if the array is empty). The second would return the first key in the array (or null). In the third, $n would be a numeric index into the array, totally unrelated to the array's keys. A positive number would indicate how far into the array to go, a negative number would indicate how far backward into the array to go, while 0 or an out of bounds index might either quietly return a null or might throw an error or warning. Some Examples: $array = array( 1 = One, two = Two, -3 = Minus Three ); echo $array[array_firstkey($array)]; // returns One because array_firstkey() returns 1 echo $array[array_lastkey($array)]; // returns Minus Three because array_lastkey() returns -3 echo $array[array_element_key($array,1)]; // returns One because array_element_key() returns 1 echo $array[array_element_key($array,2)]; // returns Two because array_element_key() returns two echo $array[array_element_key($array,-2)]; // returns Two because array_element_key() returns two echo $array[array_element_key($array,-1)]; // returns Minus Three because array_element_key() returns -3 -- Edit this bug report at http://bugs.php.net/?id=15330edit=1 -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
[PHP-DEV] Bug #15330 Updated: An efficient way to access the last element of an array is sorely missed
ID: 15330 Updated by: [EMAIL PROTECTED] Reported By: [EMAIL PROTECTED] Status: Bogus Bug Type: Feature/Change Request Operating System: N/A PHP Version: 4.1.1 New Comment: Aha! Now I see array_slice() -- much closer to that I was proposing. However, it still does not get you the value you are after directly, but an array (sans original keys) you then have to delve into for your value. Still, closer. Also, I've found the well-hidden information on getting a CVS account, so no need for that pointer now. Thanks again. --HaigEK Previous Comments: [2002-02-04 10:03:15] [EMAIL PROTECTED] Yes, I am aware of end(). It certainly has a purpose and a use, but it isn't at all the same as what I was suggesting. Frankly, I never use the internal pointer features of arrays, as they were at first alien to me, and later seemed unreliable when I thought I understood them. Providing altenative methods for ding things in programming language as otherwise accomodating as PHP, seems to me, precisely in character with its philosophy. I would be more than happy to contribute these functions myself, if someone will point me in the right direction to do so. Thank you. --HaigEK [2002-02-01 15:11:56] [EMAIL PROTECTED] These functions have been available for a long time and are well documented in the manual--see the previous comment. Torben [2002-02-01 14:38:56] [EMAIL PROTECTED] While there is no way to set the internal pointer (afaik) to a given element #, you can set the pointer to the first/last/next/previous item. http://se.php.net/manual/en/function.end.php end -- Set the internal pointer of an array to its last element. -- mats [2002-02-01 14:07:08] [EMAIL PROTECTED] There seems to be no easy and efficient way to access the last element of an array (assuming you don't already know the key to that element). The most concise, though not terribly efficient workaround I have discovered is... $array[array_pop(array_keys($array))] ...which first extracts all the keys of the array, then pops off the last key and uses it as an index into the array. Fairly easy to write and understand (though bulky), but horribly inefficient. Perhaps there is a place for new array_lastkey($array), array_firstkey($array), and array_element_key($array, $n) functions. The first of these functions would simply return the last key in the array (or null if the array is empty). The second would return the first key in the array (or null). In the third, $n would be a numeric index into the array, totally unrelated to the array's keys. A positive number would indicate how far into the array to go, a negative number would indicate how far backward into the array to go, while 0 or an out of bounds index might either quietly return a null or might throw an error or warning. Some Examples: $array = array( 1 = One, two = Two, -3 = Minus Three ); echo $array[array_firstkey($array)]; // returns One because array_firstkey() returns 1 echo $array[array_lastkey($array)]; // returns Minus Three because array_lastkey() returns -3 echo $array[array_element_key($array,1)]; // returns One because array_element_key() returns 1 echo $array[array_element_key($array,2)]; // returns Two because array_element_key() returns two echo $array[array_element_key($array,-2)]; // returns Two because array_element_key() returns two echo $array[array_element_key($array,-1)]; // returns Minus Three because array_element_key() returns -3 -- Edit this bug report at http://bugs.php.net/?id=15330edit=1 -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
[PHP-DEV] Bug #15330 Updated: An efficient way to access the last element of an array is sorely missed
ID: 15330
Updated by: [EMAIL PROTECTED]
Reported By: [EMAIL PROTECTED]
Status: Bogus
Bug Type: Feature/Change Request
Operating System: N/A
PHP Version: 4.1.1
New Comment:
Well, if you wouldn't worry about using the internal
pointers, you'd have an easier time of this. :) You can
do what you need very trivially (note that I'm not saying
these functions shouldn't be added to PHP, just that this
is already easy to do in userland):
For instance:
function array_first_key($array) {
reset($array);
return key($array);
}
function array_last_key($array) {
end($array);
return key($array);
}
...for the *_value() versions, use current() instead of
key(). For the index searcher, you can do something like:
function array_element_key($array, $element) {
if (abs($element) count($array)) {
return false;
}
if ($element 0) {
for ($i = -1, end($array); $i $element; $i--, prev($array));
} else {
for ($i = 0, reset($array); $i $element; $i++,
next($array));
}
return key($array);
}
...and so on.
Hope this helps until (if) these get added to the language.
Email me privately if you want the whole batch of
functions.
Torben
Previous Comments:
[2002-02-04 10:30:39] [EMAIL PROTECTED]
Aha! Now I see array_slice() -- much closer to that I was proposing.
However, it still does not get you the value you are after directly,
but an array (sans original keys) you then have to delve into for your
value. Still, closer.
Also, I've found the well-hidden information on getting a CVS account,
so no need for that pointer now. Thanks again.
--HaigEK
[2002-02-04 10:03:15] [EMAIL PROTECTED]
Yes, I am aware of end(). It certainly has a purpose and a use, but it
isn't at all the same as what I was suggesting.
Frankly, I never use the internal pointer features of arrays, as they
were at first alien to me, and later seemed unreliable when I thought I
understood them.
Providing altenative methods for ding things in programming language
as otherwise accomodating as PHP, seems to me, precisely in character
with its philosophy.
I would be more than happy to contribute these functions myself, if
someone will point me in the right direction to do so. Thank you.
--HaigEK
[2002-02-01 15:11:56] [EMAIL PROTECTED]
These functions have been available for a long time and are
well documented in the manual--see the previous comment.
Torben
[2002-02-01 14:38:56] [EMAIL PROTECTED]
While there is no way to set the internal pointer (afaik) to a given
element #, you can set the pointer to the first/last/next/previous
item.
http://se.php.net/manual/en/function.end.php
end -- Set the internal pointer of an array to its last element.
--
mats
[2002-02-01 14:07:08] [EMAIL PROTECTED]
There seems to be no easy and efficient way to access the last element
of an array (assuming you don't already know the key to that element).
The most concise, though not terribly efficient workaround I have
discovered is...
$array[array_pop(array_keys($array))]
...which first extracts all the keys of the array, then pops off the
last key and uses it as an index into the array. Fairly easy to write
and understand (though bulky), but horribly inefficient.
Perhaps there is a place for new array_lastkey($array),
array_firstkey($array), and array_element_key($array, $n) functions.
The first of these functions would simply return the last key in the
array (or null if the array is empty). The second would return the
first key in the array (or null). In the third, $n would be a numeric
index into the array, totally unrelated to the array's keys. A
positive number would indicate how far into the array to go, a
negative number would indicate how far backward into the array to go,
while 0 or an out of bounds index might either quietly return a null or
might throw an error or warning.
Some Examples:
$array = array( 1 = One, two = Two, -3 = Minus Three );
echo $array[array_firstkey($array)]; // returns One because
array_firstkey() returns 1
echo $array[array_lastkey($array)]; // returns Minus Three because
array_lastkey() returns -3
echo $array[array_element_key($array,1)]; // returns One because
array_element_key() returns 1
echo $array[array_element_key($array,2)]; // returns Two because
array_element_key() returns two
echo $array[array_element_key($array,-2)]; // returns Two because
array_element_key() returns two
echo $array[array_element_key($array,-1)]; // returns Minus
[PHP-DEV] Bug #15330 Updated: An efficient way to access the last element of an array is sorely missed
ID: 15330 Comment by: [EMAIL PROTECTED] Old Reported By: [EMAIL PROTECTED] Reported By: [EMAIL PROTECTED] Status: Open Bug Type: Feature/Change Request Operating System: N/A PHP Version: 4.1.1 New Comment: While there is no way to set the internal pointer (afaik) to a given element #, you can set the pointer to the first/last/next/previous item. http://se.php.net/manual/en/function.end.php end -- Set the internal pointer of an array to its last element. -- mats Previous Comments: [2002-02-01 14:07:08] [EMAIL PROTECTED] There seems to be no easy and efficient way to access the last element of an array (assuming you don't already know the key to that element). The most concise, though not terribly efficient workaround I have discovered is... $array[array_pop(array_keys($array))] ...which first extracts all the keys of the array, then pops off the last key and uses it as an index into the array. Fairly easy to write and understand (though bulky), but horribly inefficient. Perhaps there is a place for new array_lastkey($array), array_firstkey($array), and array_element_key($array, $n) functions. The first of these functions would simply return the last key in the array (or null if the array is empty). The second would return the first key in the array (or null). In the third, $n would be a numeric index into the array, totally unrelated to the array's keys. A positive number would indicate how far into the array to go, a negative number would indicate how far backward into the array to go, while 0 or an out of bounds index might either quietly return a null or might throw an error or warning. Some Examples: $array = array( 1 = One, two = Two, -3 = Minus Three ); echo $array[array_firstkey($array)]; // returns One because array_firstkey() returns 1 echo $array[array_lastkey($array)]; // returns Minus Three because array_lastkey() returns -3 echo $array[array_element_key($array,1)]; // returns One because array_element_key() returns 1 echo $array[array_element_key($array,2)]; // returns Two because array_element_key() returns two echo $array[array_element_key($array,-2)]; // returns Two because array_element_key() returns two echo $array[array_element_key($array,-1)]; // returns Minus Three because array_element_key() returns -3 Edit this bug report at http://bugs.php.net/?id=15330edit=1 -- PHP Development Mailing List http://www.php.net/ To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] To contact the list administrators, e-mail: [EMAIL PROTECTED]
