I have a variable which should be any number between 1 and 50.
It could also be any string/empty string.
I have a code written below. The point is when the variable contains string.
I don't want the code below to error out. Instead fall in the else bucket.
You don't have an "else bucket"; dothis_2 will be executed if either the numerical test or dothis_1 fails.
How can I test a variable to see if its in the right format?
The format for the variable would be 'DDMMYYYY HH:MM:SS' and is passed from a command line argument.
Any help would be appreciated (2 Replies)
hi forum
i beginning with script and i want test un null variable in a schell
i just don t know the syntax here is a litle example
y=test
echo $y
unset y
echo $y (so here Y = Null)
if Y=Null
then
echo "y is null"
exit
fi (1 Reply)
I'm using the following line in bash to test whether an argument supplied is an absolute path or not:
if echo $1 | grep '^/' > /dev/null
then
absolute=1
else
absoute=0
fi
The line appears to work but seems somewhat unprofessional looking to me. Is it an acceptable... (2 Replies)
hi,
i store a constant in a variable and want to test whether it is M or Z.
how can i achieve this?? please help
variable='M'
if
then
ehco 'success'
fi;
is this right ?? (2 Replies)
I'm trying to test and see whether a variable that is being extracted from a line in a file is numeric or not. I have tried everything that I can think of and I cannot figure out how to get it to work. I am trying to test and see if the string extracted contains 5 numeric digits. This is what I... (8 Replies)
This is the code:
while test 1 -eq 1
do
read a
$a
if test $a = stop
then
break
fi
done
I read a command on every loop an execute it.
I check if the string equals the word stop to end the loop,but it say that I gave too many arguments to test.
For example echo hello.
Now the... (1 Reply)
Hello, Unix-forums!
My problem:
read -p "Enter any number, please" number
sleep 1
echo $number | tr -d 0-9
test -z $number && echo "Thank you" || echo "This is not a number"Test always displays "This is not a number". It doesn't matter if I entered a or 1.
But if I order
echo... (2 Replies)
Hi,
I am trying to get the oracle variables and pass the values in sql placed in procedure.
VARIABLE
vstat='ASDS,FGDS,VCGD,VCXC'
Query :
select distinct dept from College
where section in ('C','D')
AND CODES =''
AND NAMES IN ('RAJ','SAM');
I want CODES values to be taken from vstat... (1 Reply)
Hello,
I have two files, f1 and f2. f1 has 5 columns like so:
a b c d 154
e f g h 365
.....
f2 has two columns, the first column contains the name of the above file and second column contains a constant which is to be used for division.
e.g.
file1 56
I want to divide the 5th... (2 Replies)
Discussion started by: Gussifinknottle
2 Replies
LEARN ABOUT PHP
empty
EMPTY(3) 1 EMPTY(3)empty - Determine whether a variable is emptySYNOPSIS
bool empty (mixed $var)
DESCRIPTION
Determine whether a variable is considered to be empty. A variable is considered empty if it does not exist or if its value equals FALSE.
empty(3) does not generate a warning if the variable does not exist.
PARAMETERS
o $var
- Variable to be checked
Note
Prior to PHP 5.5, empty(3) only supports variables; anything else will result in a parse error. In other words, the follow-
ing will not work: empty(trim($name)). Instead, use trim($name) == false.
No warning is generated if the variable does not exist. That means empty(3) is essentially the concise equivalent to !isset($var)
|| $var == false.
RETURN VALUES
Returns FALSE if $var exists and has a non-empty, non-zero value. Otherwise returns TRUE.
The following things are considered to be empty:
o "" (an empty string)
o 0 (0 as an integer)
o 0.0 (0 as a float)
o "0" (0 as a string)
o NULL
o FALSE
o array() (an empty array)
o $var; (a variable declared, but without a value)
CHANGELOG
+--------+---------------------------------------------------+
|Version | |
| | |
| | Description |
| | |
+--------+---------------------------------------------------+
| 5.5.0 | |
| | |
| | empty(3) now supports expressions, rather than |
| | only variables. |
| | |
| 5.4.0 | |
| | |
| | Checking non-numeric offsets of strings returns |
| | TRUE. |
| | |
+--------+---------------------------------------------------+
EXAMPLES
Example #1
A simple empty(3) / isset(3) comparison.
<?php
$var = 0;
// Evaluates to true because $var is empty
if (empty($var)) {
echo '$var is either 0, empty, or not set at all';
}
// Evaluates as true because $var is set
if (isset($var)) {
echo '$var is set even though it is empty';
}
?>
Example #2
empty(3) on String Offsets
PHP 5.4 changes how empty(3) behaves when passed string offsets.
<?php
$expected_array_got_string = 'somestring';
var_dump(empty($expected_array_got_string['some_key']));
var_dump(empty($expected_array_got_string[0]));
var_dump(empty($expected_array_got_string['0']));
var_dump(empty($expected_array_got_string[0.5]));
var_dump(empty($expected_array_got_string['0.5']));
var_dump(empty($expected_array_got_string['0 Mostel']));
?>
Output of the above example in PHP 5.3:
bool(false)
bool(false)
bool(false)
bool(false)
bool(false)
bool(false)
Output of the above example in PHP 5.4:
bool(true)
bool(false)
bool(false)
bool(false)
bool(true)
bool(true)
NOTES
Note
Because this is a language construct and not a function, it cannot be called using variable functions.
Note
When using empty(3) on inaccessible object properties, the __isset() overloading method will be called, if declared.
SEE ALSO isset(3), __isset(), unset(3), array_key_exists(3), count(3), strlen(3), The type comparison tables.
PHP Documentation Group EMPTY(3)