大约有 48,000 项符合查询结果（耗时：0.0772秒） [XML]
Array vs. Object efficiency in JavaScript
I have a model with possibly thousands of objects. I was wondering what would be the most efficient way of storing them and retrieving a single object once I have it's id. The id's are long numbers.
...
Why is the Java main method static?
...ntire class - sometimes you have an instance that hasn't been initialized, and you have to check for it in every method that could be called.
There are just too many edge cases and ambiguities for it to make sense for the JVM to have to instantiate a class before the entry point is called. That's ...
How to convert a string to an integer in JavaScript?
...k for you, then there are the parseInt, unary plus, parseFloat with floor, and Math.round methods.
parseInt:
var x = parseInt("1000", 10); // you want to use radix 10
// so you get a decimal number even with a leading 0 and an old browser ([IE8, Firefox 20, Chrome 22 and older][1])
unary plu...
Checking for empty arrays: count vs empty
...y, was empty — i.e., as though it had no elements). This is problematic, and another example of PHP being too forgiving.
– Matthew Slyman
Apr 5 '17 at 4:59
...
Can I export a variable to the environment from a bash script without sourcing it?
...to have the script, rather than setting an environment variable, print commands that will set the environment variable:
$ cat set-vars2.sh
#!/bin/bash
echo export FOO=BAR
$ eval "$(./set-vars2.sh)"
$ echo "$FOO"
BAR
A third approach is to have a script that sets your environment variable(s) inter...
How to find out which package version is loaded in R?
...cluster. It has 2 versions of R installed. System wide R 2.11 (Debian 6.0) and R 2.14.2 in non-standard location.
12 Answe...
Android error: Failed to install *.apk on device *: timeout
I'm getting this error from time to time and don't know what causing this:
When trying to run/debug an Android app on a real device (Galaxy Samsung S in my case) I'm getting the following error in the Console:
...
Asynchronous Process inside a javascript for loop [duplicate]
...ronous operations are started. When they complete some time in the future and call their callbacks, the value of your loop index variable i will be at its last value for all the callbacks.
This is because the for loop does not wait for an asynchronous operation to complete before continuing on t...
Something better than .NET Reflector? [closed]
...h is absolutely ridiculous), half the time the update doesn't go smoothly, and it is increasingly hindering my productivity with each update. I am sick of it, and I am ready for something better. Is there a better disassembler?
...
Can I install Python 3.x and 2.x on the same Windows computer?
I'm running Windows and the shell/OS automatically runs Python based on the registry settings when you run a program on the command line. Will this break if I install a 2.x and 3.x version of Python on the same machine?
...