大约有 40,000 项符合查询结果（耗时：0.0443秒） [XML]
Run a callback only if an attribute has changed in Rails
...eRecord::Base
before_save :do_something, if: :will_save_change_to_status_id?
private
def do_something
# ...
end
end
The commit that changed ActiveRecord::Dirty is here: https://github.com/rails/rails/commit/16ae3db5a5c6a08383b974ae6c96faac5b4a3c81
Here is a blog post on these change...
How to get the class of the clicked element?
...
"class" is not a valid variable name.
– Fred Bergman
Oct 20 '09 at 9:17
1
...
CSS: center element within a element
... text-align:center;
background-color:blue;
height:400px;
width:600px;
}
.block {
height:100px;
width:200px;
text-align:left;
}
.center {
margin:auto;
background-color:green;
}
.left {
margin:auto auto auto 0;
background-color:red;
}
.right ...
How can I disable a button on a jQuery UI dialog?
...
If you're including the .button() plugin/widget that jQuery UI contains (if you have the full library and are on 1.8+, you have it), you can use it to disable the button and update the state visually, like this:
$(".ui-dialog-buttonpane button:contains('Confirm')")....
Regex replace uppercase with lowercase letters
...e, you can just use ?: in the inner groups (i.e. non capture groups) or avoid creating them at all:
Find: ((?:[a-z][A-Z]+)|(?:[A-Z]+[a-z])) OR ([a-z][A-Z]+|[A-Z]+[a-z])
Replace: \L$1
2016-06-23 Edit
Tyler suggested by editing this answer an alternate find expression for #4:
(\B)([A-Z]+)
Acc...
Android - shadow on text?
I am wondering how to add shadow on text in android?
6 Answers
6
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Execute stored procedure with an Output parameter?
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I think the answer by Jaider below completes this answer since I myself would be interested in the written command and not the mouse solution.
– Alwyn Schoeman
Dec 6 '17 at 2:30
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Best way to do multi-row insert in Oracle?
...
This works in Oracle:
insert into pager (PAG_ID,PAG_PARENT,PAG_NAME,PAG_ACTIVE)
select 8000,0,'Multi 8000',1 from dual
union all select 8001,0,'Multi 8001',1 from dual
The thing to remember here is to use the from dual statement.
(source)
...
How to add footnotes to GitHub-flavoured Markdown?
...r superscript tags, e.g. <sup>1</sup>.
¹Of course this isn't ideal, as you are now responsible for maintaining the numbering of your footnotes. It works reasonably well if you only have one or two, though.
shar...
How to drop rows of Pandas DataFrame whose value in a certain column is NaN
...
This question is already resolved, but...
...also consider the solution suggested by Wouter in his original comment. The ability to handle missing data, including dropna(), is built into pandas explicitly. Aside from potentially improved performance over doing it manually, these...