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Is there a performance difference between a for loop and a for-each loop?
...
From Item 46 in Effective Java by Joshua Bloch :
The for-each loop, introduced in
release 1.5, gets rid of the clutter
and the opportunity for error by
hiding the iterator or index variable
completely. The resulti...
When should assertions stay in production code? [closed]
...mments, which is a helpful way of thinking about them. They are a step up from comments because they are constantly machine tested during development, but they should always be meaningful to human readers first. Just like comments, they should not be part of logic or final execution. Just like co...
Performance optimization strategies of last resort [closed]
...tried to explain this in a Dr. Dobbs article in November 1993, by starting from a conventionally well-designed non-trivial program with no obvious waste and taking it through a series of optimizations until its wall-clock time was reduced from 48 seconds to 1.1 seconds, and the source code size was ...
When is .then(success, fail) considered an antipattern for promises?
...h(e) {
logger.log(e);
}
The catch logger will also handle exceptions from the success logger call.
So much for the difference.
I don't quite understand its explanation as for the try and catch
The argument is that usually you want to catch errors in every step of the processing, and tha...
Java Generics: Cannot cast List to List? [duplicate]
...t;? extends Tree> b1 = a1;
... because then you can only fetch things from b1, and they're guaranteed to be compatible with Tree. You can't call b1.add(...) precisely because the compiler won't know whether it's safe or not.
Have a look at this section of Angelika Langer's Java Generics FAQ fo...
Bash script to receive and repass quoted parameters
... "$@" works with any Bourne shell or Bourne shell derivative (from 1978 onwards), including Korn and Bash. Probably 95% of the time, using "$@" is correct and $* is wrong.
– Jonathan Leffler
Jan 16 '09 at 8:03
...
Python : List of dict, if exists increment a dict value, if not append a new dict
...ecial data structure, defaultdict, created just to make this even easier:
from collections import defaultdict # available in Python 2.5 and newer
urls_d = defaultdict(int)
for url in list_of_urls:
urls_d[url] += 1
If you access the defaultdict using a key, and the key is not already in the ...
How to specify maven's distributionManagement organisation wide?
...arent pom file project (with packaging 'pom') generically for all projects from your organization.
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.or...
When and why to 'return false' in JavaScript?
...return false;">...
The 'return false;' in this case stops the browser from jumping to the current location, as indicated by the href="#" - instead, only doSomeFunction() is executed. It's useful for when you want to add events to anchor tags, but don't want the browser jumping up and down to e...
How to stop event bubbling on checkbox click
...ubbling of an event to
parent elements, preventing any parent
handlers from being notified of the
event.
event.preventDefault()
Prevents the browser from executing
the default action. Use the method
isDefaultPrevented to know whether
this method was ever called (on that
event ob...