How do I check if a variable consisted of letters, numbers or both letters and numbers?
For example, I have a variable $X and I want to print "1" if it contains only letters, "2" if it contains only numbers and "3" if it contains both (2 Replies)
Hello all I am a unix newbie....
I have a sun netra t1 and it is freaking out
I am connected to it through a console port, and it is just spitting out a ton on numbers and letters like below its just keeps going and going.
I have tried rebooting it and I cannot get it back to any kind of a... (1 Reply)
Hi friends
How can I use "for loop" for decimal numbers?
ex: 0.1 < x < 0.6
I used this commands but does'nt work.
LIMIT=0.6
for ((x=0.1; x<=LIMIT; x++))
do
-
-
-
done
Many thanks (1 Reply)
Hello...
I am new to unix and I am wondering if in a C-shell script , Are we supposed to use only whole numbers........ for example..if a program needs to calculate the average of some numbers........
@ avg = (($1 +$2 + $3)/3)) is returning a whole number.........How can a decimal be... (7 Replies)
If I have a set of strings,
C21
F231
H42
1C10
1F113
and I want to isolate the ints following the char, what would the sed string be to find numbers after letters?
If I do,
*, I will get numbers after letters, but I am looking to do something like,
sed 's/*/\t*/g'
this will give me... (14 Replies)
Hi,
I columns with both number and letters however i need the number 4 trimmed off the lines that have 3 numbers in them so it just because the 2 preceding numbers only
For example
V25QG2-K18QG-V25CG2
L26HG-L17HA-L26CG
I434QD1-L19HB2-I434CD1
I434QD1-A31QB-I434CD1 ... (7 Replies)
Hi Experts,
I am finding difficulty to get exact match:
file
OPERATING_SYSTEM=HP-UX
LOOPBACK_ADDRESS=127.0.0.1
INTERFACE_NAME="lan3"
IP_ADDRESS="10.53.52.241"
SUBNET_MASK="255.255.255.192"
BROADCAST_ADDRESS=""
INTERFACE_STATE=""
DHCP_ENABLE=0
INTERFACE_NAME="lan3:1"... (6 Replies)
Hello,
I have a file such as this:
chr1
chr2
chr1
chr2
chr3
chr10
chr4
chr5
chrz
chr1AI want to sort it, I use this command:
sort -k1 -th -n testfilebut I get this output, how can I fix this?
chr1
chr1
chr10
chr1A
chr2
chr2 (3 Replies)
I have a file with hundreds of lines in it. I wanted to extract anything that matches the following:
KR followed by 4 digits:
example KR1201
cat list | sed "s///g"
Is the closest I've come, and obviously it is not what I want. This would remove all of the items that I want and leave me... (2 Replies)
Heyas
Just a little fun script (code block) i'd like to share for fun.
#/bin/bash
# roman.sh
#
# Function
#
num2roman() { # NUM
# Returns NUM in roman letters
#
input=$1 # input num
output="" # Clear output string
len=${#input} # Initial length to count down
... (9 Replies)
Discussion started by: sea
9 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)