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Why does Java switch on contiguous ints appear to run faster with added cases?
...value has been removed in JDK 8 after more benchmarking was performed.
Finally, when the method becomes too long (> 25 cases in my tests), it is in not inlined any longer with the default JVM settings - that is the likeliest cause for the drop in performance at that point.
With 5 cases, the d...
When should I use uuid.uuid1() vs. uuid.uuid4() in python?
...d4() generates, as you said, a random UUID. The chance of a collision is really, really, really small. Small enough, that you shouldn't worry about it. The problem is, that a bad random-number generator makes it more likely to have collisions.
This excellent answer by Bob Aman sums it up nicely. (I...
How to dismiss keyboard for UITextView with return key?
...urn key is pressed, the keyboard for UITextView will disappear. But actually the return key can only act as '\n'.
34 ...
Is there a way to perform “if” in python's lambda
...
If you still want to print you can import future module
from __future__ import print_function
f = lambda x: print(x) if x%2 == 0 else False
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Why does viewWillAppear not get called when an app comes back from the background?
...
In other words, if someone looks at another application or takes a phone call, then switches back to your app which was earlier on backgrounded, your UIViewController which was already visible when you left your app 'doesn't care' so to speak -- as far as it is concerned, it's never disappeared and...
Linux command to print directory structure in the form of a tree
... /proc
|-- fd
| `-- 3 -> /proc/15589/fd
|-- fdinfo
|-- net
| |-- dev_snmp6
| |-- netfilter
| |-- rpc
| | |-- auth.rpcsec.context
| | |-- auth.rpcsec.init
| | |-- auth.unix.gid
| | |-- auth.unix.ip
| | |-- nfs4.idtoname
| | |-- nfs4.nametoid
| | |-- nfsd.export
...
What's the shebang/hashbang (#!) in Facebook and new Twitter URLs for?
...
Are you sure that is all there is to it? I often find that the page loading hangs on a shebang URL on facebook (even after many reloads), but if you manually remove the #!, it works. Not to mention you often get "1.5 URLs" (i.e. the old URL remai...
How Many Seconds Between Two Dates?
...Z, NN, EE, 0, 0, 0, 0);
var dif = t1.getTime() - t2.getTime();
var Seconds_from_T1_to_T2 = dif / 1000;
var Seconds_Between_Dates = Math.abs(Seconds_from_T1_to_T2);
A handy source for future reference is the MDN site
Alternatively, if your dates come in a format javascript can parse
var dif = Da...
How to perform Callbacks in Objective-C
...newer) option is to use blocks:
@interface MyClass: NSObject
{
void (^_completionHandler)(int someParameter);
}
- (void) doSomethingWithCompletionHandler:(void(^)(int))handler;
@end
@implementation MyClass
- (void) doSomethingWithCompletionHandler:(void(^)(int))handler
{
// NOTE: copyin...
Handling optional parameters in javascript
... second argument is a function or not:
function getData (id, parameters, callback) {
if (arguments.length == 2) { // if only two arguments were supplied
if (Object.prototype.toString.call(parameters) == "[object Function]") {
callback = parameters;
}
}
//...
}
You can also us...