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C++ sorting and keeping track of indexes
... supply your original index vector, sort function, comparator, or automatically reorder v in the sort_indexes function using an extra vector.
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UIWebView open links in Safari
...h reference to the answer and comments below.
– Toby Allen
Mar 23 '11 at 22:08
How to go back to the application once ...
Python argparse: Make at least one argument required
...
args = vars(parser.parse_args())
if not any(args.values()):
parser.error('No arguments provided.')
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Explicitly select items from a list or tuple
... myBigList[i] for i in [87, 342, 217, 998, 500] ]
20.6 usec: map(myBigList.__getitem__, (87, 342, 217, 998, 500))
22.7 usec: itemgetter(87, 342, 217, 998, 500)(myBigList)
24.6 usec: list( myBigList[i] for i in [87, 342, 217, 998, 500] )
Note that in Python 3, the 1st was changed to be the same as ...
How to read a file in reverse order?
...A correct, efficient answer written as a generator.
import os
def reverse_readline(filename, buf_size=8192):
"""A generator that returns the lines of a file in reverse order"""
with open(filename) as fh:
segment = None
offset = 0
fh.seek(0, os.SEEK_END)
file...
How to generate keyboard events in Python?
...om ctypes import wintypes
import time
user32 = ctypes.WinDLL('user32', use_last_error=True)
INPUT_MOUSE = 0
INPUT_KEYBOARD = 1
INPUT_HARDWARE = 2
KEYEVENTF_EXTENDEDKEY = 0x0001
KEYEVENTF_KEYUP = 0x0002
KEYEVENTF_UNICODE = 0x0004
KEYEVENTF_SCANCODE = 0x0008
MAPVK_VK_TO_VSC = 0
# ...
In pure functional languages, is there an algorithm to get the inverse function?
...
In some cases, yes! There's a beautiful paper called Bidirectionalization for Free! which discusses a few cases -- when your function is sufficiently polymorphic -- where it is possible, completely automatically to derive an inverse function. (It also discusses what makes...
Is “double hashing” a password less secure than just hashing it once?
...o compute a hash for each password and see if it matches the stored hash.
All passwords are not equally likely. Attackers might exhaustively search all short passwords, but they know that their chances for brute-force success drop sharply with each additional character. Instead, they use an ordered...
Change a Django form field to a hidden field
...get the value.
also you may prefer to use in the view:
form.fields['field_name'].widget = forms.HiddenInput()
but I'm not sure it will protect save method on post.
Hope it helps.
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What is the fastest way to check if a class has a function defined?
...tr() to get the attribute, and callable() to verify it is a method:
invert_op = getattr(self, "invert_op", None)
if callable(invert_op):
invert_op(self.path.parent_op)
Note that getattr() normally throws exception when the attribute doesn't exist. However, if you specify a default value (None...