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What's the difference between getPath(), getAbsolutePath(), and getCanonicalPath() in Java?
...f what Sun like to call "hierarchical pathnames" (basically a path like c:/foo.txt or /usr/muggins). This is why you create files in terms of paths. The operations you are describing are all operations upon this "pathname".
getPath() fetches the path that the File was created with (../foo.txt)
get...
Validating parameters to a Bash script
... it as a commentar). i did "$#" to fix it. second, the regex also matches "foo123bar". i fixed it by doing ^[0-9]+$. you may also fix it by using grep's -x option
– Johannes Schaub - litb
Mar 31 '09 at 1:21
...
Java Enum definition
...
It still allows me to create a class Foo extends Node<City> where Foo is unrelated to City.
– newacct
Nov 23 '11 at 22:43
1
...
“for” vs “each” in Ruby
...
Never ever use for it may cause almost untraceable bugs.
Don't be fooled, this is not about idiomatic code or style issues. Ruby's implementation of for has a serious flaw and should not be used.
Here is an example where for introduces a bug,
class Library
def initialize
@ary = []
...
How do I dump an object's fields to the console?
...
The to_yaml method seems to be useful sometimes:
$foo = {:name => "Clem", :age => 43}
puts $foo.to_yaml
returns
---
:age: 43
:name: Clem
(Does this depend on some YAML module being loaded? Or would that typically be available?)
...
How to update PATH variable permanently from Windows command line?
...nvironment:PATH=...
...
> REM ## Query env-var:
> setenv.py PATH C:\foo
!!!Cannot access HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment:PATH due to: [WinError 5] Access is denied
!!!Cannot find HKEY_CURRENT_USER\Environment:PATH due to: [WinError 2] The syst...
What does the “at” (@) symbol do in Python?
...ons and class definitions
for more about decorators.
So, we see that
@foo
def bar():
pass
is semantically the same as:
def bar():
pass
bar = foo(bar)
They are not exactly the same because Python evaluates the foo expression (which could be a dotted lookup and a function call) befo...
how does array[100] = {0} set the entire array to 0?
...d the initialiser.
If your array is auto, then it is another story.
int foo(void)
{
char array[100] = {0};
...
}
In this case at every call of the function foo you will have a hidden memset.
The code above is equivalent to
int foo(void)
{
char array[100];
memset(array, 0, sizeof(array));
.....
How do I get the object if it exists, or None if it does not exist?
... python is to wrap it in a try catch:
try:
go = SomeModel.objects.get(foo='bar')
except SomeModel.DoesNotExist:
go = None
What I did do, is to subclass models.Manager, create a safe_get like the code above and use that manager for my models. That way you can write: SomeModel.objects.safe_...
What does the “static” modifier after “import” mean?
... fields / method of a class instead of:
package test;
import org.example.Foo;
class A {
B b = Foo.B_INSTANCE;
}
You can write :
package test;
import static org.example.Foo.B_INSTANCE;
class A {
B b = B_INSTANCE;
}
It is useful if you are often used a constant from another class in yo...