大约有 43,000 项符合查询结果（耗时：0.0464秒） [XML]
Determine the number of NA values in a column
...r of NA values in a data frame column. Say my data frame is called df , and the name of the column I am considering is col . The way I have come up with is following:
...
How to disable scrolling in UITableView table when the content fits on the screen
... a few (grouped style) tables in my iphone app (only on part of the screen and added with Interface Builder though, not subclassed from UITableViewController ) that 80% of the time are small and will fit on the screen. When the table fits on the screen, I'd like to disable scrolling, to make it ...
Adding one day to a date
...se fatal errors when run on your host ;)
– Henrik Erlandsson
Jan 13 '15 at 13:18
Don't apologize. Some people posted t...
Do I have to Close() a SQLConnection before it gets disposed?
...
Since you have a using block, the Dispose method of the SQLCommand will be called and it will close the connection:
// System.Data.SqlClient.SqlConnection.Dispose disassemble
protected override void Dispose(bool disposing)
{
if (disposing)
{
this._userConnectionOptions =...
【内核源码】linux UDP实现 - 操作系统(内核) - 清泛网 - 专注C/C++及内核技术
...n += sizeof(struct udphdr); //否则开始一个新的udp包
/*
* Get and verify the address.
*/
if (msg->msg_name) {
DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
if (msg->msg_namelen < sizeof(*usin))
return -EINVAL;
if (usin->sin_family != AF_INET) {
if (u...
What is the reason for having '//' in Python? [duplicate]
...
In Python 3, they made the / operator do a floating-point division, and added the // operator to do integer division (i.e. quotient without remainder); whereas in Python 2, the / operator was simply integer division, unless one of the operands was already a floating point number.
In Python 2...
Notepad++ Multi editing
...
Yes: simply press and hold the Alt key, click and drag to select the lines whose columns you wish to edit, and begin typing.
You can also go to Settings > Preferences..., and in the Editing tab, turn on multi-editing, to enable selection o...
Git: See my last commit
...s noted by other folks in this question, you can use git log -1, git show, and git diff to get the same sort of output. Personally, I tend to use git show <rev> when looking at individual revisions.
share
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Add number of days to a date
...time
expects to be given a string containing a US English date format and will try to parse that format into a Unix timestamp (the number of seconds since January 1 1970 00:00:00 UTC), relative to the timestamp given in now, or the current time if now is not supplied.
while date
Returns ...
How do I convert a Django QuerySet into list of dicts?
...dicts its actually a <class 'django.db.models.query.ValuesQuerySet'> and not a list.
– dm03514
Oct 18 '11 at 18:31
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