大约有 40,000 项符合查询结果（耗时：0.0500秒） [XML]
What is 'Pattern Matching' in functional languages?
...wesome.
Algebraic data types in a nutshell
ML-like functional languages allow you define simple data types called "disjoint unions" or "algebraic data types". These data structures are simple containers, and can be recursively defined. For example:
type 'a list =
| Nil
| Cons of 'a * 'a ...
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
# ...
How to permanently set $PATH on Linux/Unix? [closed]
...t. The actual solution depends on the purpose.
The variable values are usually stored in either a list of assignments or a shell script that is run at the start of the system or user session. In case of the shell script you must use a specific shell syntax and export or set commands.
System wide
...
File Upload without Form
... using jQuery. The input tag is not inside any form tag. It stands individually. So I don't want to use jQuery plugins like 'ajaxForm' or 'ajaxSubmit'.
...
How do I output an ISO 8601 formatted string in JavaScript?
...
There is already a function called toISOString():
var date = new Date();
date.toISOString(); //"2011-12-19T15:28:46.493Z"
If, somehow, you're on a browser that doesn't support it, I've got you covered:
if ( !Date.prototype.toISOString ) {
( functi...
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.
share
|
improv...
How to extract the n-th elements from a list of tuples?
...
@Wayne Werner: Yep. This stuff was all just passive knowledge (I don't often use it) - but it's good to be reminded now and then so you know where / what to look for...
– Daren Thomas
Jul 22 '10 at 13:14
...
Scala: write string to file in one statement
...or encoding-safe. If an exception happens in write(), close will never be called, and the file won't be closed. PrintWriter also uses the default system encoding, which is very bad for portability. And finally, this approach generates a separate class specifically for this line (however, given that ...
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...