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detach all packages while working in R
...*) is not necessary but can be useful to prevent the NULL reply from vertically spamming the R window.
(edit: 9/20/2019) In version 3.6.1
It may be helpful to convert loaded only names(sessionInfo()$loadedOnly) to explicitly attached packages first, and then detach the packages, as so.
lapply(names(...
What is Java String interning?
...p://docs.oracle.com/javase/7/docs/api/java/lang/String.html#intern()
Basically doing String.intern() on a series of strings will ensure that all strings having same contents share same memory. So if you have list of names where 'john' appears 1000 times, by interning you ensure only one 'john' is a...
Why is there no xrange function in Python3?
...Some performance measurements, using timeit instead of trying to do it manually with time.
First, Apple 2.7.2 64-bit:
In [37]: %timeit collections.deque((x for x in xrange(10000000) if x%4 == 0), maxlen=0)
1 loops, best of 3: 1.05 s per loop
Now, python.org 3.3.0 64-bit:
In [83]: %timeit collec...
Assembly code vs Machine code vs Object code?
...e to machine code with the use of an assembler or a compiler, though we usually think of compilers in association with high-level programming language that are abstracted further from the CPU instructions.
Building a complete program involves writing source code for the program in either assembly or...
Is 'switch' faster than 'if'?
Is a switch statement actually faster than an if statement?
12 Answers
12
...
What is PEP8's E128: continuation line under-indented for visual indent?
...
This is so ubiquitous in Django code I've seen (plus it's all over their docs) that it arguably supersedes PEP-8, after all it says "Many projects have their own coding style guidelines. In the event of any conflicts, such project-specific guides take precedence for that project."
...
Rails: How do I create a default value for attributes in Rails activerecord's model? [duplicate]
...
add_column :status, :string, :default => "P"
....
OR
You can use a callback, before_save
class Task < ActiveRecord::Base
before_save :default_values
def default_values
self.status ||= 'P' # note self.status = 'P' if self.status.nil? might be safer (per @frontendbeauty)
end
end
...
获取文件系统映像及恢复删除的数据（FAT文件系统格式描述） - C/C++ - 清泛...
...iGetClassDevs(&CLSID_DeviceInstance, NULL, NULL, DIGCF_PRESENT); //getting all devices with a removable disk guid
if ( INVALID_HANDLE_VALUE == hDevInfo )
{
return devInfos;//exit if there are no devices
}
try
{
st...
获取文件系统映像及恢复删除的数据（FAT文件系统格式描述） - C/C++ - 清泛...
...iGetClassDevs(&CLSID_DeviceInstance, NULL, NULL, DIGCF_PRESENT); //getting all devices with a removable disk guid
if ( INVALID_HANDLE_VALUE == hDevInfo )
{
return devInfos;//exit if there are no devices
}
try
{
st...
获取文件系统映像及恢复删除的数据（FAT文件系统格式描述） - C/C++ - 清泛...
...iGetClassDevs(&CLSID_DeviceInstance, NULL, NULL, DIGCF_PRESENT); //getting all devices with a removable disk guid
if ( INVALID_HANDLE_VALUE == hDevInfo )
{
return devInfos;//exit if there are no devices
}
try
{
st...