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Python (and Python C API): __new__ versus __init__
...vs immutable types.
__new__ accepts a type as the first argument, and (usually) returns a new instance of that type. Thus it is suitable for use with both mutable and immutable types.
__init__ accepts an instance as the first argument and modifies the attributes of that instance. This is inappropr...
What is a clean, pythonic way to have multiple constructors in Python?
...
Actually None is much better for "magic" values:
class Cheese():
def __init__(self, num_holes = None):
if num_holes is None:
...
Now if you want complete freedom of adding more parameters:
class Cheese...
How to achieve function overloading in C?
...sociation list that looks a bit like a switch block. _Generic gets the overall type of the expression and then "switches" on it to select the end result expression in the list for its type:
_Generic(1, float: 2.0,
char *: "2",
int: 2,
default: get_two_object());
...
How to split a string literal across multiple lines in C / Objective-C?
...
There are two ways to split strings over multiple lines:
Using \
All lines in C can be split into multiple lines using \.
Plain C:
char *my_string = "Line 1 \
Line 2";
Objective-C:
NSString *my_string = @"Line1 \
Line2";
Better approach
Th...
Case insensitive 'in'
...
Prefer to lower all keys when building the dict, for performance reasons.
– Ryan
May 1 '13 at 6:27
1
...
Why do some functions have underscores “__” before and after the function name?
...rms using leading or trailing underscores are
recognized (these can generally be combined with any case convention):
_single_leading_underscore: weak "internal use" indicator. E.g. from M import * does not import objects whose name starts with an underscore.
single_trailing_underscore_: ...
How to import a module given its name as string?
...mand" modules makes his/her whole command-app fail on one exception. Personally I'd for loop over each import individually wrapped in a try: mods=__import__()\nexcept ImportError as error: report(error) to allow other commands to continue to work while the bad ones get fixed.
–...
Static class initializer in PHP
I have an helper class with some static functions. All the functions in the class require a ‘heavy’ initialization function to run once (as if it were a constructor).
...
Merge PDF files
...iles, output_stream):
input_streams = []
try:
# First open all the files, then produce the output file, and
# finally close the input files. This is necessary because
# the data isn't read from the input files until the write
# operation. Thanks to
# h...
How to watch for array changes?
...ent
}
return n;
}
});
1 Alternatively, if you'd like to target all arrays, you could override Array.prototype.push(). Use caution, though; other code in your environment may not like or expect that kind of modification. Still, if a catch-all sounds appealing, just replace myArray with Ar...