大约有 40,000 项符合查询结果（耗时：0.0422秒） [XML]
Laravel migration: unique key is too long, even if specified
...e that VARCHAR may have 1, 2 or 4 bytes for each length unit. Example: utf8_mb4 (4 bytes) -> 767 / 4 = 191. Otherwise utf8_general_ci for VARCHAR(X) with X < 85 ( 1 byte ) = O(85) , or utf8_general_ci for VARCHAR(X) with X >= 86 ( 2 bytes ) -> 767 / 2 = 383. Consider also other columns l...
Finding current executable's path without /proc/self/exe
...
Some OS-specific interfaces:
Mac OS X: _NSGetExecutablePath() (man 3 dyld)
Linux: readlink /proc/self/exe
Solaris: getexecname()
FreeBSD: sysctl CTL_KERN KERN_PROC KERN_PROC_PATHNAME -1
FreeBSD if it has procfs: readlink /proc/curproc/file (FreeBSD doesn't have pr...
is_null($x) vs $x === null in PHP [duplicate]
... three if you count isset() ) methods to determine if a value is null: is_null() and === null . I have heard, but not confirmed, that === null is faster, but in a code review someone strongly suggested that I use is_null() instead as it is specifically designed for the null-evaluation purpo...
How do I get a file extension in PHP?
...t few people know it. Meet pathinfo():
$ext = pathinfo($filename, PATHINFO_EXTENSION);
This is fast and built-in. pathinfo() can give you other information, such as canonical path, depending on the constant you pass to it.
Remember that if you want to be able to deal with non ASCII characters, y...
What is the (function() { } )() construct in JavaScript?
...nswered Nov 22 '11 at 14:21
gion_13gion_13
38.3k99 gold badges9090 silver badges101101 bronze badges
...
An example of how to use getopts in bash
...ere it shouldn't, so change it into just h (without colon)
to expect -p any_string, you need to add p: to the argument list
Basically : after the option means it requires the argument.
The basic syntax of getopts is (see: man bash):
getopts OPTSTRING VARNAME [ARGS...]
where:
OPTSTRING is s...
Context switches much slower in new linux kernels
...erformance problem in recent kernels has to do with the switch to the intel_idle cpuidle driver from acpi_idle, the driver used in older kernels. Sadly, the intel_idle driver ignores the user's BIOS configuration for the C-states and dances to its own tune. In other words, even if you completely dis...
Project structure for Google App Engine
... had trouble with packages. Just make sure each of your sub folders has an __init__.py file. It's ok if its empty.
Boilerplate files
These hardly vary between projects
app.yaml: direct all non-static requests to main.py
main.py: initialize app and send it all requests
Project lay-out
static...
What does “SyntaxError: Missing parentheses in call to 'print'” mean in Python?
...lt;module>
TypeError: unsupported operand type(s) for >>: 'builtin_function_or_method' and '_io.TextIOWrapper'. Did you mean "print(<message>, file=<output_stream>)"?
Since this error is raised when the code runs, rather than when it is compiled, it doesn't have access to the ...
How to create fixed space and flexible space bar button items programmatically?
..."Today" style:UIBarButtonItemStylePlain target:self action:@selector(update_baritem:)];
todayItem.tag = 2;
UIBarButtonItem *cashItem = [[UIBarButtonItem alloc] initWithTitle:@"Cash" style:UIBarButtonItemStylePlain target:self action:@selector(update_baritem:)];
cashItem.tag = 3;
UIBarButtonItem *c...