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Lambda function in list comprehensions
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The first one creates a single lambda function and calls it ten times.
The second one doesn't call the function. It creates 10 different lambda functions. It puts all of those in a list. To make it equivalent to the first you need:
[(lambda x: x*x)(x) for x in range(10)]
Or b...
Convert string to title case with JavaScript
...return txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase();});
};
Call it like:
"pascal".toProperCase();
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Is object empty? [duplicate]
...uming that by empty you mean "has no properties of its own".
// Speed up calls to hasOwnProperty
var hasOwnProperty = Object.prototype.hasOwnProperty;
function isEmpty(obj) {
// null and undefined are "empty"
if (obj == null) return true;
// Assume if it has a length property with a ...
Rake just one migration
...n a single migration that changed and needed to be re-run independently of all other migrations. Fire up the console and do this:
>> require 'db/migrate/your_migrations.rb'
=> ["YourMigrations"]
>> YourMigrations.up
=> etc... as the migration runs
>> YourMigration.down
Mor...
How to check if object has any properties in JavaScript?
...d Apr 20 '10 at 6:49
Daniel VassalloDaniel Vassallo
301k6666 gold badges475475 silver badges424424 bronze badges
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Force R not to use exponential notation (e.g. e+10)?
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This is a bit of a grey area. You need to recall that R will always invoke a print method, and these print methods listen to some options. Including 'scipen' -- a penalty for scientific display. From help(options):
‘scipen’: integer. A penalty to be applied wh...
@selector() in Swift?
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Community♦
111 silver badge
answered Jun 3 '14 at 5:27
ricksterrickster
115k2323 gold bad...
应用更新使用指导 · App Inventor 2 中文网
...个按钮，并显示当前版本：
when Screen1.Initialize() {
标签_版本.Text = join("当前版本 ", 应用更新1.CurrentVersionName)
}
when 按钮_检查更新.Click() {
标签_状态.Text = "正在检查…"
应用更新1.CheckUpdate("https://example.com/version.json")
}
when 应...
Understand convertRect:toView:, convertRect:FromView:, convertPoint:toView: and convertPoint:fromVie
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I always find this confusing so I made a playground where you can visually explore what the convert function does. This is done in Swift 3 and Xcode 8.1b:
import UIKit
import PlaygroundSupport
class MyViewController: UIViewController {
override func viewDidLoad() {
super.viewDidL...
Is there a built in function for string natural sort?
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There is a third party library for this on PyPI called natsort (full disclosure, I am the package's author). For your case, you can do either of the following:
>>> from natsort import natsorted, ns
>>> x = ['Elm11', 'Elm12', 'Elm2', 'elm0', 'elm1', 'elm1...