大约有 6,261 项符合查询结果（耗时：0.0159秒） [XML]
What would be C++ limitations compared C language? [closed]
...itrary subset of C++. C is not a subset of C++ at all.
This is valid C:
foo_t* foo = malloc ( sizeof(foo_t) );
To make it compile as C++ you have to write:
foo_t* foo = static_cast<foo_t*>( malloc ( sizeof(foo_t) ) );
which isn't valid C any more. (you could use the C-style cast, it wh...
How can I rename a field for all documents in MongoDB?
...
You can use:
db.foo.update({}, {$rename:{"name.additional":"name.last"}}, false, true);
Or to just update the docs which contain the property:
db.foo.update({"name.additional": {$exists: true}}, {$rename:{"name.additional":"name.last"}}, ...
Convert string in base64 to image and save on filesystem in Python
... how do you do this starting off with a non-inline str? I can't do b'foobar' because I'm not making the string inline
– Seph Reed
Jul 22 '17 at 19:22
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history.replaceState() example?
... whatever your current location href is
window.history.replaceState( {} , 'foo', '/foo' );
console.log( window.location.href ); // oh, hey, it replaced the path with /foo
There is more to replaceState() but I don't know what exactly it is that you want to do with it.
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Checking for a null int value from a Java ResultSet
...et#getObject(). Substitute -1 with whatever null-case value you want.
int foo = resultSet.getObject("foo") != null ? resultSet.getInt("foo") : -1;
Or, if you can guarantee that you use the right DB column type so that ResultSet#getObject() really returns an Integer (and thus not Long, Short or By...
What is the quickest way to HTTP GET in Python?
...mport urllib.request
contents = urllib.request.urlopen("http://example.com/foo/bar").read()
Python 2:
import urllib2
contents = urllib2.urlopen("http://example.com/foo/bar").read()
Documentation for urllib.request and read.
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What does void mean in C, C++, and C#?
...void in the argument list is optional. However, in C, it is NOT optional: foo() means it takes any number of parameters of any type, whereas foo(void) means it takes zero parameters.
– Adam Rosenfield
Jun 28 '09 at 5:00
...
Unix shell script to truncate a large file
...ou don't actually need a command to go along with the redirection:
$ echo foo > foo.txt
$ cat foo.txt
foo
$ > foo.txt
$ cat foo.txt
$
A simple redirection all by itself will clear the file.
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How to get the last N records in mongodb?
... you have some id or date field called "x" you would do ...
.sort()
db.foo.find().sort({x:1});
The 1 will sort ascending (oldest to newest) and -1 will sort descending (newest to oldest.)
If you use the auto created _id field it has a date embedded in it ... so you can use that to order by .....
How can you use optional parameters in C#?
...
In C#, I would normally use multiple forms of the method:
void GetFooBar(int a) { int defaultBValue; GetFooBar(a, defaultBValue); }
void GetFooBar(int a, int b)
{
// whatever here
}
UPDATE: This mentioned above WAS the way that I did default values with C# 2.0. The projects I'm workin...