大约有 40,000 项符合查询结果（耗时：0.0560秒） [XML]
How to import CSV file data into a PostgreSQL table?
...rticle.
Solution paraphrased here:
Create your table:
CREATE TABLE zip_codes
(ZIP char(5), LATITUDE double precision, LONGITUDE double precision,
CITY varchar, STATE char(2), COUNTY varchar, ZIP_CLASS varchar);
Copy data from your CSV file to the table:
COPY zip_codes FROM '/path/to/csv/ZI...
Is it better in C++ to pass by value or pass by constant reference?
...r iterators and for function objects (lambdas, classes deriving from std::*_function).
This was especially true before the existence of move semantics. The reason is simple: if you passed by value, a copy of the object had to be made and, except for very small objects, this is always more expensive...
Java ByteBuffer to String
...sibling getBytes() method:
byte[] bytes = k.getBytes( StandardCharsets.UTF_8 );
To put bytes with a particular encoding into a String, you can use a different String constructor:
String v = new String( bytes, StandardCharsets.UTF_8 );
Note that ByteBuffer.array() is an optional operation. If y...
Unique fields that allow nulls in Django
...pty string by providing your own customized model form for Foo with a clean_bar method that turns the empty string into None:
class FooForm(forms.ModelForm):
class Meta:
model = Foo
def clean_bar(self):
return self.cleaned_data['bar'] or None
class FooAdmin(admin.ModelAdmin...
Convert string to integer type in Go?
...64); err == nil {
fmt.Printf("i=%d, type: %T\n", i, i)
}
var i int
if _, err := fmt.Sscan(s, &i); err == nil {
fmt.Printf("i=%d, type: %T\n", i, i)
}
Output (if called with argument "123"):
i=123, type: int
i=123, type: int64
i=123, type: int
Parsing Custom strings
There is also a...
Preserving order with LINQ
...
so because OrderBy is a stable sort, then: seq.OrderBy( _ => _.Key ) will put the elements in to exactly the same order as seq.GroupBy( _ => _.Key ).SelectMany( _ => _ ). Is that correct?
– dmg
Feb 1 '16 at 22:11
...
Reliable method to get machine's MAC address in C#
...address.</returns>
private string GetMacAddress()
{
const int MIN_MAC_ADDR_LENGTH = 12;
string macAddress = string.Empty;
long maxSpeed = -1;
foreach (NetworkInterface nic in NetworkInterface.GetAllNetworkInterfaces())
{
log.Debug(
"Found MAC Address: "...
Finding out the name of the original repository you cloned from in Git
...igin -n | ruby -ne 'puts /^\s*Fetch.*(:|\/){1}([^\/]+\/[^\/]+).git/.match($_)[2] rescue nil'
It was tested with three different URL styles:
echo "Fetch URL: http://user@pass:gitservice.org:20080/owner/repo.git" | ruby -ne 'puts /^\s*Fetch.*(:|\/){1}([^\/]+\/[^\/]+).git/.match($_)[2] rescue nil'
e...
What is the copy-and-swap idiom?
...nclude <algorithm> // std::copy
#include <cstddef> // std::size_t
class dumb_array
{
public:
// (default) constructor
dumb_array(std::size_t size = 0)
: mSize(size),
mArray(mSize ? new int[mSize]() : nullptr)
{
}
// copy-constructor
dumb_array(...
Fatal error: “No Target Architecture” in Visual Studio
...
_WIN32 identifier is not defined.
use #include <SDKDDKVer.h>
MSVS generated projects wrap this include by generating a local "targetver.h"which is included by "stdafx.h" that is comiled into a precompiled-header throu...