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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 ...
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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Should I use `import os.path` or `import os`?
...ant to use rather than a thing in the os module, so even though it's not really a submodule of a package called os, I import it sort of like it is one and I always do import os.path. This is consistent with how os.path is documented.
Incidentally, this sort of structure leads to a lot of Python p...
“Bitmap too large to be uploaded into a texture”
...
All rendering is based on OpenGL, so no you can't go over this limit (GL_MAX_TEXTURE_SIZE depends on the device, but the minimum is 2048x2048, so any image lower than 2048x2048 will fit).
With such big images, if you want to...
Divide a number by 3 without using *, /, +, -, % operators
...n which performs the desired operation. But it requires the + operator, so all you have left to do is to add the values with bit-operators:
// replaces the + operator
int add(int x, int y)
{
while (x) {
int t = (x & y) << 1;
y ^= x;
x = t;
}
return y;
}...
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
# ...
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...
关于php的socket初探 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...塞的古老模型：属于同步阻塞 IO 模型，代码如下：
socket_server.php
<?php
/**
* SocketServer Class
* By James.Huang <shagoo#gmail.com>
**/
set_time_limit(0);
class SocketServer
{
private static $socket;
function SocketServer($port)
{ ...