大约有 44,000 项符合查询结果（耗时：0.0685秒） [XML]
Any reason not to use '+' to concatenate two strings?
...e Python interpreter has to create a new string object for each iteration, and it ends up taking quadratic time. (Recent versions of CPython can apparently optimize this in some cases, but other implementations can't, so programmers are discouraged from relying on this.) ''.join is the right way t...
How to cast an object in Objective-C
... Great answer. You could make it a little clearer by breaking out the cast and assignment into two lines.
– Guido Anselmi
Jun 3 '14 at 21:06
1
...
Is it possible to declare a variable in Gradle usable in Java?
... in Java ?
Basically I would like to declare some vars in the build.gradle and then getting it (obviously) at build time. Just like a pre-processor macros in C/C++...
...
CSS hexadecimal RGBA?
...and need to create CSS from it at runtime. This requires the extra step of converting from hex to decimal if you want to add alpha to it, which is clunky.
– Beejor
May 5 '15 at 15:17
...
JavaScript checking for null vs. undefined and difference between == and ===
...perands are of different types, === will always return false while == will convert one or both operands into the same type using rules that lead to some slightly unintuitive behaviour. If the operands are of the same type (e.g. both are strings, such as in the typeof comparison above), == and === wi...
Iterate over model instance field names and values in template
...ts have changed slightly. A migration guide has been provided to assist in converting your code to use the new, official API.
In the below example, we will utilize the formalized method for retrieving all field instances of a model via Client._meta.get_fields():
fields = [(f.verbose_name, f.name) f...
What's the result of += in C and C++?
...
Semantics of the compound assignment operators is different in C and C++:
C99 standard, 6.5.16, part 3:
An assignment operator stores a value in the object designated by the left operand. An
assignment expression has the value of the left operand after the assignment, but is not an
...
Running bash script from within python
... subprocess.check_call("./script.sh '%s'" % arg, shell=True)
Remember to convert the args to string before passing, using str(arg).
This can be used to pass as many arguments as desired:
subprocess.check_call("./script.ksh %s %s %s" % (arg1, str(arg2), arg3), shell=True)
...
JavaScript: Check if mouse button down?
...what button is pressed, be prepared to make mouseDown an array of counters and count them separately for separate buttons:
// let's pretend that a mouse doesn't have more than 9 buttons
var mouseDown = [0, 0, 0, 0, 0, 0, 0, 0, 0],
mouseDownCount = 0;
document.body.onmousedown = function(evt) { ...
Python string.join(list) on object array rather than string array
...on thing in the universe: join("sep", list) - and all elements of list get converted to their string representations. I've been really struggling to find a solution in python.
– Jason
Feb 23 '18 at 13:12
...