Hi,
I am writing a BASH script. My questions regard deleting elements of arrays.
I have an array:
michael-browns-powerbook-g4-15:~ msb65$ test_array=(1 2 3 4)
michael-browns-powerbook-g4-15:~ msb65$ echo ${test_array}
1 2 3 4
To delete the second element of test_array I type:... (3 Replies)
Hi,
I'm trying to write a function that redirects the contents of an
array to a file. The array contains the lines of a data file with
white space.
The function seems to preserve all white space when redirected
except that it seems to ignore newlines. As a consequence, the
elements of the... (7 Replies)
i have a file,like
1 3
4 5
6 7
8 9
i want to save it into an array.
and then i want to get every element, because i want to use them to calculate. for example: i want to calculate 1 + 3.
but i cannot reach my goal.
open (FILE, "<", "number");
my @arr;
while (<FILE>){
chomp;... (1 Reply)
Hi there.
i have created a program that in the end it will give output like this
1 2 3 4 5
10 9 8 7 6
11 12 13 14 15
.............. 17
i wonder how to save the output into a single string and into a file.
i.e 1 10 11 12 9 2 3 8 13 14 7 4 5 6 15 17 (in this order,... (3 Replies)
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known data:
Hi there.
i have created a program that in the end it will give output like this
1 2 3 4 5
10 9 ... (1 Reply)
Hi, I have an ksh array(ARR). the elements to the array are file names. i need to go to each file in the array and manipulate the records.
for name in ${files}; do ---this loop is for all the file names in the array
for i in $(wc -l < $name); do --this loop is for all the records in... (20 Replies)
Hello,
I have a simple task and I am having some trouble with the syntax. I have a variable with an assigned value,
CMD_STRING='-L 22 -s 0 -r -O -A i -N 100 -n'
I would like to add that variable to an array. As far as I have been able to look up, the syntax should be something like,
... (4 Replies)
I'm working on a script to execute a number of items. One being, editing particular files to add certain lines. I'm attempting to utilize sed, but, having issues when running from a bash script. Assistance is greatly appreciated.
My example:
sed -i '14 i\
# add these lines
add these lines to... (5 Replies)
I am trying to select a file in bash and save it to a directory. The below does run but no selected file is saved. Thank you :).
bash
# select file
printf "please select a file to analyze with entered gene or genes \n"
select file in $(cd... (4 Replies)
Discussion started by: cmccabe
4 Replies
LEARN ABOUT PHP
unset
UNSET(3) 1 UNSET(3)unset - Unset a given variableSYNOPSIS
void unset (mixed $var, [mixed $...])
DESCRIPTION unset(3) destroys the specified variables.
The behavior of unset(3) inside of a function can vary depending on what type of variable you are attempting to destroy.
If a globalized variable is unset(3) inside of a function, only the local variable is destroyed. The variable in the calling environment
will retain the same value as before unset(3) was called.
<?php
function destroy_foo()
{
global $foo;
unset($foo);
}
$foo = 'bar';
destroy_foo();
echo $foo;
?>
The above example will output:
bar
To unset(3) a global variable inside of a function, then use the $GLOBALS array to do so:
<?php
function foo()
{
unset($GLOBALS['bar']);
}
$bar = "something";
foo();
?>
If a variable that is PASSED BY REFERENCE is unset(3) inside of a function, only the local variable is destroyed. The variable in the
calling environment will retain the same value as before unset(3) was called.
<?php
function foo(&$bar)
{
unset($bar);
$bar = "blah";
}
$bar = 'something';
echo "$bar
";
foo($bar);
echo "$bar
";
?>
The above example will output:
something
something
If a static variable is unset(3) inside of a function, unset(3) destroys the variable only in the context of the rest of a function. Fol-
lowing calls will restore the previous value of a variable.
<?php
function foo()
{
static $bar;
$bar++;
echo "Before unset: $bar, ";
unset($bar);
$bar = 23;
echo "after unset: $bar
";
}
foo();
foo();
foo();
?>
The above example will output:
Before unset: 1, after unset: 23
Before unset: 2, after unset: 23
Before unset: 3, after unset: 23
PARAMETERS
o $var
- The variable to be unset.
o $...
- Another variable ...
RETURN VALUES
No value is returned.
EXAMPLES
Example #1
unset(3) example
<?php
// destroy a single variable
unset($foo);
// destroy a single element of an array
unset($bar['quux']);
// destroy more than one variable
unset($foo1, $foo2, $foo3);
?>
Example #2
Using (unset) casting
(unset) casting is often confused with the unset(3) function. (unset) casting serves only as a NULL-type cast, for completeness. It
does not alter the variable it's casting.
<?php
$name = 'Felipe';
var_dump((unset) $name);
var_dump($name);
?>
The above example will output:
NULL
string(6) "Felipe"
NOTES
Note
Because this is a language construct and not a function, it cannot be called using variable functions.
Note
It is possible to unset even object properties visible in current context.
Note
It is not possible to unset $this inside an object method since PHP 5.
Note
When using unset(3) on inaccessible object properties, the __unset() overloading method will be called, if declared.
SEE ALSO isset(3), empty(3), __unset(), array_splice(3).
PHP Documentation Group UNSET(3)