Re: Beginners query
| From: | Wan Chaowei | Date: | Fri, 02 Jan 2015 21:31:50 +0000 |
| Subject: | Re: Beginners query | ||
| References: | 1 2 | Groups: | php.general |
| Request: | Send a blank email to php-general+get-324216@lists.php.net to get a copy of this message | ||
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"Jim Giner" 写入消息 news:D1.99.60454.91F55A45@pb1.pair.com...
On 1/1/2015 3:28 AM, Sachin Raut wrote:
> Happy New Year to all members of PHP group.
>
> I just want to know the difference between following 3 statements. Or are
> they all does the same thing.
>
> 1. isset($a)
> 2. !empty($a)
> 3. $a!=""
>
> Thanks
> Sachin
>
1 - tells you if a var is defined
2 - tells you if the var is null or not yet defined.
3 - using this as an 'if' condition tells you whether a var is 'not
equal' to null
plz more note false, null, 0, and empty string, in this case the are same
BTW - all of this can be found in the manual online. You should spend
the time to read some of the introductory items.