大约有 32,000 项符合查询结果（耗时：0.0438秒） [XML]
How can I detect if a selector returns null?
....exists = function(){
return this.length > 0 ? this : false;
}
So then you can do something like this:
var firstExistingElement =
$('#iDontExist').exists() || //<-returns false;
$('#iExist').exists() || //<-gets assigned to the variable
$('#iExistAsWell')....
Find and replace in file and overwrite file doesn't work, it empties the file
...ng sh rather than bash, so if you're aiming for portability (or posixness) then you'll need to avoid that construction.
– Norman Gray
Aug 4 '16 at 9:05
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Extracting specific columns from a data frame
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@ArenCambre: then your data.frame isn't really named df. df is also a function in the stats package.
– Joshua Ulrich
Apr 10 '12 at 2:58
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Get DateTime.Now with milliseconds precision
... want to show the samples in the right order, with "pretty good" accuracy, then the system clock should be fine. I'd advise you to use DateTime.UtcNow rather than DateTime.Now though, to avoid time zone issues around daylight saving transitions, etc.
If your question is actually just around convert...
How do I replace text inside a div element?
...pted way is to loop through the childNodes, call removeNode(true) on each, then append new nodes created using document.createElement() or document.createTextNode(). If you need to do that I would recommend writing a function to avoid a lot of typing.
– Joel Anair
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Install a Windows service using a Windows command prompt?
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If the directory's name has a space like c:\program files\abc 123, then you must use double quotes around the path.
installutil.exe "c:\program files\abc 123\myservice.exe"
It makes things much easier if you set up a bat file like following,
e.g. To install a service, create a "myservi...
Which browsers support ?
...orrect way to do it now, but it was the only widely supported way to do it then. For example IE10p2 supported async="true" but did not support async="async"
– Philip Rieck
Feb 18 '14 at 16:10
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Set the layout weight of a TextView programmatically
...ifferent LayoutParams are not interchangeable and if you use the wrong one then nothing seems to happen. The text view's parent is a table row, hence:
http://developer.android.com/reference/android/widget/TableRow.LayoutParams.html
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Check list of words in another string [duplicate]
...ase string are, and how often they change. If performance is not an issue then go for the simplest, which is probably Kenny's.
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How to make grep only match if the entire line matches?
...on in regards of @hakre ):
If you want to match a string starting with -, then you should use -- with grep. Whatever follows -- will be taken as an input (not option).
Example:
echo -f |grep -- "-f" # where grep "-f" will show error
echo -f |grep -F -- "-f" # whre grep -F "-f" will show erro...