大约有 40,000 项符合查询结果（耗时：0.0516秒） [XML]
jQuery: checking if the value of a field is null (empty)
...ype]').val().length != 0){}
If you want to check if the element exist at all, you should do that before calling val:
var $d = $('#person_data[document_type]');
if ($d.length != 0) {
if ($d.val().length != 0 ) {...}
}
s...
What is the difference between `after_create` and `after_save` and when to use which?
... readers should note that, according to the docs, ActiveRecord's update_all does not invoke any callbacks, including after_*
– user2426679
Jan 10 at 19:34
add a comment
...
Easiest way to check for an index or a key in an array?
... associative array)
[ ${array[key]+abc} ] && echo "exists"
Basically what ${array[key]+abc} does is
if array[key] is set, return abc
if array[key] is not set, return nothing
References:
See Parameter Expansion in Bash manual and the little note
if the colon is omitted, the ope...
Gesture recognizer and button actions
...nizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
// Disallow recognition of tap gestures in the segmented control.
if ((touch.view == yourButton)) {//change it to your condition
return NO;
}
return YES;
}
hope it will help
Edit
As Daniel noted you must con...
Octave-Gnuplot-AquaTerm error: set terminal aqua enhanced title “Figure 1”…unknown terminal type"
I've installed Octave and gnuplot via Homebrew, and downloaded AquaTerm.dmg.
When I try to plot, I get the following message:
...
What are the most interesting equivalences arising from the Curry-Howard Isomorphism?
...nd C-H to many interesting logics and formulations of logics to obtain a really wide variety of correspondences. Here I've tried to focus on some of the more interesting ones rather than on the obscure, plus a couple of fundamental ones that haven't come up yet.
evaluation | proof norm...
In c++ what does a tilde “~” before a function name signify?
... memory, etc. etc.
Here's a description from ibm.com:
Destructors are usually used to deallocate memory and do other cleanup for a class object and its class members when the object is destroyed. A destructor is called for a class object when that object passes out of scope or is explicitly delete...
Git interactive rebase no commits to pick
... pushed
for your second question: have a branch with your changes (basically a configuration branch) and regularly merge the other branches into it. this way the changes will not move to other branches
share
|
...
Dialog to pick image from gallery or from camera
Is there a standard way to call dialog box with choose either to pick an image from the camera or to get from gallery (like in build-in phone book or Skype)?
...
When to use os.name, sys.platform, or platform.system?
...specific modules are available (e.g. posix, nt, ...)
platform.system() actually runs uname and potentially several other functions to determine the system type at run time.
My suggestion:
Use os.name to check whether it's a posix-compliant system.
Use sys.platform to check whether it's a linux,...