大约有 40,000 项符合查询结果（耗时：0.0522秒） [XML]
php出现 Notice: Undefined index: xxx 的解决方法 - 更多技术 - 清泛网 - 专注C/C++及内核技术
php出现 Notice: Undefined index: xxx 的解决方法Php_Notice_Undefined_index出现 "Undefined index: xxx "警告的原因：PHP 本身不需要事先声明变量即可直接使用，但是对未声明变量会有提示，最好的办法是使用变量之前先检查变量是否存在。出现"...
Find UNC path of a network drive?
...
The answer is a simple PowerShell one-liner:
Get-WmiObject Win32_NetworkConnection | ft "RemoteName","LocalName" -A
If you only want to pull the UNC for one particular drive, add a where statement:
Get-WmiObject Win32_NetworkConnection | where -Property 'LocalName' -eq 'Z:' | ft "Remo...
error LNK2019: unresolved external symbol _WinMain@16 referenced in function ___tmainCRTStartup
...you can just hint at what your entry point is, because you haven't defined ___tmainCRTStartup. You can do this by adding the following to Properties -> Linker -> Command line:
/ENTRY:"mainCRTStartup"
This way you get rid of the console window.
...
Pros and Cons of Interface constants [closed]
...mple of a good enough and a bad use:
Bad:
interface User {
const TYPE_ADMINISTRATOR = 1;
const TYPE_USER = 2;
const TYPE_GUEST = 3;
}
Good Enough:
interface HTTPRequest_1_1 {
const TYPE_CONNECT = 'connect';
const TYPE_DELETE = 'delete';
const TYPE_GET ...
How to initialize an array in one step using Ruby?
...rray = [ '1', '2', '3' ]
You can also use a range:
array = ('1'..'3').to_a # parentheses are required
# or
array = *('1'..'3') # parentheses not required, but included for clarity
For arrays of whitespace-delimited strings, you can use Percent String syntax:
array = %w[ 1 2 3 ]
You can...
Are unused CSS images downloaded?
... </style>
</head>
<body>
<?php if(isset($_GET['foo'])) {
file_put_contents('test.txt', $_SERVER['HTTP_USER_AGENT']);
} ?>
</body>
</html>
If test.txt is populated with the browser's user agent, then the image is downloaded. This was not the ...
How can I programmatically check whether a keyboard is present in iOS app?
...ade easier to use.
@interface KeyboardStateListener : NSObject {
BOOL _isVisible;
}
+ (KeyboardStateListener *)sharedInstance;
@property (nonatomic, readonly, getter=isVisible) BOOL visible;
@end
static KeyboardStateListener *sharedInstance;
@implementation KeyboardStateListener
+ (KeyboardS...
Why does comparing strings using either '==' or 'is' sometimes produce a different result?
... 23yr old Jack, but its not the same person.
class Person(object):
def __init__(self, name, age):
self.name = name
self.age = age
def __eq__(self, other):
return self.name == other.name and self.age == other.age
jack1 = Person('Jack', 23)
jack2 = Person('Jack', 23)
jac...
What is the meaning of “POSIX”?
...iew/osfoundations.html . For Windows, see en.wikipedia.org/wiki/POSIX#POSIX_for_Windows : Posix compliance is currently included in Enterprise and Ultimate editions only (not in the cheaper ones!-), though you can get partways w/Cygwin, en.wikipedia.org/wiki/Cygwin .
– Alex Mar...
How to add a custom loglevel to Python's logging facility
... example that checks if the logging level is enabled:
import logging
DEBUG_LEVELV_NUM = 9
logging.addLevelName(DEBUG_LEVELV_NUM, "DEBUGV")
def debugv(self, message, *args, **kws):
if self.isEnabledFor(DEBUG_LEVELV_NUM):
# Yes, logger takes its '*args' as 'args'.
self._log(DEBUG...