You don't want 9 processes writing to the same file at the same time. They may interfere with each other, overwriting each others' lines, etc.
It's looking for the string 'variable' because you put it in //, just give it the variable. You didn't even name it 'variable' though, you named it 'var'. Try $2 ~ var
In summary, I'd do this:
Depending on whether your disk's faster than your processor or vice versa, there may be ways to speed this up by running multiple gunzip's at once. I'm not sure how to do that yet but I'll think about it.
folks,
In my working directory, there a multiple large files which only contain one line in the file. The line is too long to use "grep", so any help?
For example, if I want to find if these files contain a string like "93849", what command I should use?
Also, there is oder_id number... (1 Reply)
Hi,
I'm trying to figure out the best solution to the following problem, and I'm not
yet that much experienced like you. :-)
Basically I have to read a fairly large file, composed of "messages" , in order
to display all of them through an user interface (made with QT).
The messages that... (3 Replies)
I have the following situation:
a text file with 50000 string patterns:
abc2344536
gvk6575556
klo6575556
....
and 3 text files each with more than 1 million lines:
...
000000 abc2344536 46575 0000
000000 abc2344536 46575 4444
000000 abc2344555 46575 1234
...
I... (8 Replies)
I met a problem on HPUX with 64G RAM and 20 CPU.
There are 5 million files with file name from file0000001.dat to file9999999.dat, in the same directory, and with some other files with random names.
I was trying to remove all the files from file0000001.dat to file9999999.dat at the same time.... (9 Replies)
How to search a string which has occured numerous times in a single row. I tried many options, I am facing issue with the file size. Anything I go for, it says it is huge.. File is 82MB.
Assume, the file contains the string 'Name' in many places.. Something Like below.
... (5 Replies)
Hi
When i copy 300GB of data from one filesystem to the other filesystem in AIX I get the error :
tar: 0511-825 The file 'SAPBRD.dat' is too large.
The command I used is :
# tar -cf - . | (cd /sapbackup ; tar -xf - )
im copying as root
The below is my ulimit -a output :
... (3 Replies)
Hello Friends,
I have the below scenario in my current project. Suggest me which tool ( perl,python etc) is best to this scenario. Or should I go for Programming language ( C/Java )..
(1) I will be having a very big file ( information about 200million subscribers will be stored in it ). This... (5 Replies)
This basic code works.
I have a very long list, almost 10000 lines that I am building into the array. Each line has either 2 or 3 fields as shown in the code snippit. The array elements are static (for a few reasons that out of scope of this question) the list has to be "built in".
It... (5 Replies)
Hi Friends,
I have a file with sample amount data as follows:
-89990.3456
8788798.990000128
55109787.20
-12455558989.90876
I need to exclude the '-' symbol in order to treat all values as an absolute one and then I need to sum up.The record count is around 1 million.
How... (8 Replies)
I have nginx web server logs with all requests that were made and I'm filtering them by date and time.
Each line has the following structure:
127.0.0.1 - xyz.com GET 123.ts HTTP/1.1 (200) 0.000 s 3182 CoreMedia/1.0.0.15F79 (iPhone; U; CPU OS 11_4 like Mac OS X; pt_br)
These text files are... (21 Replies)
Discussion started by: brenoasrm
21 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)