大约有 3,095 项符合查询结果（耗时：0.0321秒） [XML]
Unique constraint that allows empty values in MySQL
...he codes are unique, but some products simply doesn't have a code. I can't invent codes because those are providers codes.
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Django fix Admin plural
... a model somewhere in your own code you'll use this property instead of re-inventing the wheel.
– cibyr
Mar 10 '14 at 3:33
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Propagate all arguments in a bash shell script
...ere is historical progression here; $* did not work as designed, so $@ was invented to replace it; but the quoting rules being what they are, the double quotes around it are still required (or it will revert to the broken $* semantics).
– tripleee
Dec 15 '15 at...
How can I have a newline in a string in sh?
...ho's problems were the reason why the Unix Standardization process finally invented the printf utility, doing away with all the problems.
So to get a newline in a string:
FOO="hello
world"
BAR=$(printf "hello\nworld\n") # Alternative; note: final newline is deleted
printf '<%s>\n' "$FOO"
pri...
How to pass the value of a variable to the stdin of a command?
...s continues until you type a line containing 'quit'. You can be endlessly inventive with how you handle it. Beware the old urban legend of a program that stopped working when the users began working with Ecuador. They'd type in the name of the capital, Quito, and the program exited.
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Explode PHP string by new line
...ould ever use your snippet. The most direct / sensible technique for your invented string would be var_export(preg_split('~\R+~', $a, 0, PREG_SPLIT_NO_EMPTY)); Anything else is simply not clever. Demo
– mickmackusa
Sep 16 at 15:02
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Enum “Inheritance”
...ns above using classes with int constants lack type-safety. I.e. you could invent new values actually not defined in the class.
Furthermore it is not possible for example to write a method taking one of these classes as input.
You would need to write
public void DoSomethingMeaningFull(int consumeV...
What is a 'thunk'?
...ynamic behavior when referencing an apparently static object. The term was invented by Brian Wichmann, who when asked to explain pass-by-name said "Well you go out to load the value from memory and then suddenly - thunk - there you are evaluating an expression."
Thunks have been put in hardware (cf...
$(document).click() not working correctly on iPhone. jquery [duplicate]
...ry with a data-href html attribute which is shown above (this attribute is invented by myself and is not a standard jQuery or HTML data attribute.)
$(document).on('click', '.clickable-div', function() {
document.location = $(this).data('href');
});
This will work on your desktop browser but...
C语言结构体里的成员数组和指针 - c++1y / stl - 清泛IT社区，为创新赋能！
单看这文章的标题，你可能会觉得好像没什么意思。你先别下这个结论，相信这篇文章会对你理解C语言有帮助。这篇文章产生的背景是在微博上，看到@Laruence同学出了一个关于C语言的题，微博链接。微博截图如下。我觉得好多...