PYTHON list

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Python replacement for PHP's list [ edit | history ]
array = ('foo', 'bar', 'foobar')
# Assigns all values.
(foo, bar, foobar) = array
#Prints 'foo - bar - foobar'
print '%s - %s - %s' % (foo, bar, foobar)

For single assignments, the tuple must have an ending comma, otherwise a ValueError is raised.

In Python, unlike PHP's list(), you cannot just skip an assignment with a space or by ignoring the other items. You also may not assign one variable and leave all other assignments blank. A simple solution is to just use an underscore:

array = ('foo', 'bar', 'foobar')
# Assigning some values
(foo, _, _) = array
# Skipping
(_,_,foo2) = array
# Prints 'foo - foobar'
print '%s - %s' % (foo, foo2)

PHP list

PHP original manual for list [ show | php.net ]

list

(PHP 4, PHP 5)

listAssign variables as if they were an array

Description

void list ( mixed $varname [, mixed $... ] )

Like array(), this is not really a function, but a language construct. list() is used to assign a list of variables in one operation.

Parameters

varname

A variable.

Return Values

No value is returned.

Examples

Example #1 list() examples

<?php

$info 
= array('coffee''brown''caffeine');

// Listing all the variables
list($drink$color$power) = $info;
echo 
"$drink is $color and $power makes it special.\n";

// Listing some of them
list($drink, , $power) = $info;
echo 
"$drink has $power.\n";

// Or let's skip to only the third one
list( , , $power) = $info;
echo 
"I need $power!\n";

// list() doesn't work with strings
list($bar) = "abcde";
var_dump($bar); // NULL
?>

Example #2 An example use of list()

<table>
 <tr>
  <th>Employee name</th>
  <th>Salary</th>
 </tr>

<?php

$result 
mysql_query("SELECT id, name, salary FROM employees"$conn);
while (list(
$id$name$salary) = mysql_fetch_row($result)) {
    echo 
" <tr>\n" .
          
"  <td><a href=\"info.php?id=$id\">$name</a></td>\n" .
          
"  <td>$salary</td>\n" .
          
" </tr>\n";
}

?>

</table>

Example #3 Using nested list()

<?php

list($a, list($b$c)) = array(1, array(23));

var_dump($a$b$c);

?>
int(1)
int(2)
int(3)

Example #4 Using list() with array indices

<?php

$info 
= array('coffee''brown''caffeine');

list(
$a[0], $a[1], $a[2]) = $info;

var_dump($a);

?>

Gives the following output (note the order of the elements compared in which order they were written in the list() syntax):

array(3) {
  [2]=>
  string(8) "caffeine"
  [1]=>
  string(5) "brown"
  [0]=>
  string(6) "coffee"
}

Notes

Warning

list() assigns the values starting with the right-most parameter. If you are using plain variables, you don't have to worry about this. But if you are using arrays with indices you usually expect the order of the indices in the array the same you wrote in the list() from left to right; which it isn't. It's assigned in the reverse order.

Note: list() only works on numerical arrays and assumes the numerical indices start at 0.

See Also

  • each() - Return the current key and value pair from an array and advance the array cursor
  • array() - Create an array
  • extract() - Import variables into the current symbol table from an array