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Differences between action and actionListener
...just specify exactly that string in the action attribute. Thus, this is totally clumsy:
<h:commandLink value="Go to next page" action="#{bean.goToNextpage}" />
With this senseless method returning a hardcoded string:
public String goToNextpage() {
return "nextpage";
}
Instead, just put t...
Inheritance and Overriding __init__ in python
...
The book is a bit dated with respect to subclass-superclass calling. It's also a little dated with respect to subclassing built-in classes.
It looks like this nowadays:
class FileInfo(dict):
"""store file metadata"""
def __init__(self, filename=None):
super(FileInfo,...
How to save all the variables in the current python session?
I want to save all the variables in my current python environment. It seems one option is to use the 'pickle' module. However, I don't want to do this for 2 reasons:
...
Gzip versus minify
...Apr 30 '09 at 14:20
Paul KuykendallPaul Kuykendall
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...
Define a lambda expression that raises an Exception
...ur goal is to avoid a def, this obviously doesn't cut it. It does, however allow you to conditionally raise exceptions, e.g.:
y = lambda x: 2*x if x < 10 else raise_(Exception('foobar'))
Alternatively you can raise an exception without defining a named function. All you need is a strong stom...
Why is the order in dictionaries and sets arbitrary?
...der:
>>> {'bar': None, 'foo': None}
{'foo': None, 'bar': None}
All slots except 3 and 4 are empty, looping over the table first lists slot 3, then slot 4, so 'foo' is listed before 'bar'.
bar and baz, however, have hash values that are exactly 8 apart and thus map to the exact same slot...
Is it ever advantageous to use 'goto' in a language that supports loops and functions? If so, why?
...o this already):
Cleanly exiting a function
Often in a function, you may allocate resources and need to exit in multiple places. Programmers can simplify their code by putting the resource cleanup code at the end of the function, and all "exit points" of the function would goto the cleanup label....
What does the “yield” keyword do?
... list, you can read its items one by one. Reading its items one by one is called iteration:
>>> mylist = [1, 2, 3]
>>> for i in mylist:
... print(i)
1
2
3
mylist is an iterable. When you use a list comprehension, you create a list, and so an iterable:
>>> mylist = [...
Error handling in getJSON calls
How can you handle errors in a getJSON call? Im trying to reference a cross-domain script service using jsonp, how do you register an error method?
...
How to automatically generate a stacktrace when my program crashes
... the GCC compiler. When my C++ program crashes I would like it to automatically generate a stacktrace.
28 Answers
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