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Add a reference column migration in Rails 4
...t; ActiveRecord::Migration
def change
add_reference :uploads, :user, index: true
end
end
Then, run the migration using rake db:migrate.
This migration will take care of adding a new column named user_id to uploads table (referencing id column in users table), PLUS it will also add an index...
In an array of objects, fastest way to find the index of an object whose attributes match a search
...field' attribute:
var elementPos = array.map(function(x) {return x.id; }).indexOf(idYourAreLookingFor);
var objectFound = array[elementPos];
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What is the most efficient way to loop through dataframes with pandas? [duplicate]
...s of pandas now include a built-in function for iterating over rows.
for index, row in df.iterrows():
# do some logic here
Or, if you want it faster use itertuples()
But, unutbu's suggestion to use numpy functions to avoid iterating over rows will produce the fastest code.
...
Get user profile picture by Id
...k, Instagram, and gravatar. It has libraries for iOS, Android, Ruby, Node, PHP, Python, and JavaScript.
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Is it possible to make an ASP.NET MVC route based on a subdomain?
...)
{
var url = httpContext.Request.Headers["HOST"];
var index = url.IndexOf(".");
if (index < 0)
return null;
var subDomain = url.Substring(0, index);
if (subDomain == "user1")
{
var routeData = new RouteData(this, new ...
通信连接组件 · App Inventor 2 中文网
...glat
调用百度地图的uri参考地址：https://lbsyun.baidu.com/index.php?title=uri/api/web
打开系统照相机（比照相机组件打开的界面会丰富一些）
Action: android.media.action.STILL_IMAGE_CAMERA
可选取多个文件（图片、音频、...
Filtering Pandas DataFrames on dates
...
If date column is the index, then use .loc for label based indexing or .iloc for positional indexing.
For example:
df.loc['2014-01-01':'2014-02-01']
See details here http://pandas.pydata.org/pandas-docs/stable/dsintro.html#indexing-selection
...
“Unsafe JavaScript attempt to access frame with URL…” error being continuously generated in Chrome w
...I think the best solution is to use Facebook's server-side solutions (e.g. PHP SDK), it'll save you a lot, lot, lot, lot, lot of headache. The only advantage I see in using the FB javascript SDK is the popup login which you can do yourself using javascript/jQuery.
...
No increment operator (++) in Ruby? [duplicate]
...
I don't think that notation is available because—unlike say PHP or C—everything in Ruby is an object.
Sure you could use $var=0; $var++ in PHP, but that's because it's a variable and not an object. Therefore, $var = new stdClass(); $var++ would probably throw an error.
I'm not a R...
How to loop through array in jQuery?
...upported in any version of IE.
jQuery.each:
jQuery.each(substr, function(index, item) {
// do something with `item` (or `this` is also `item` if you like)
});
(Link to docs)
Advantages: All of the same advantages as forEach, plus you know it's there since you're using jQuery.
Disadvantages...