underscore

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: When we must use a _ to separate digits in a number I don't' understand the following case in which I can't use it: In positions where a string of digits is expected (as documented in the JDK7 guide here ) Some examples? 回答1: You don't have to use "_", you can . And examples given in the proposal are credit card numbers, phone numbers, or simply numbers for which it makes sense to have a separator in the code. For the "In positions where a string of digits is expected" it's simply in places where it's supposed to start (or end) with a digit.

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I am trying to split this string in python: 2.7.0_bf4fda703454 I want to split that string on the underscore _ so that I can use the value on the left side. 回答1: "2.7.0_bf4fda703454".split("_") gives a list of strings: In [1]: "2.7.0_bf4fda703454".split("_") Out[1]: ['2.7.0', 'bf4fda703454'] This splits the string at every underscore. If you want it to stop after the first split, use "2.7.0_bf4fda703454".split("_", 1) . If you know for a fact that the string contains an underscore, you can even unpack the LHS and RHS into separate variables:

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I'm exploring the idea of using Webpack with Backbone.js . I've followed the quick start guide and has a general idea of how Webpack works, but I'm unclear on how to load dependency library like jquery / backbone / underscore. Should they be loaded externally with <script> or is this something Webpack can handle like RequireJS's shim? According to the webpack doc: shimming modules , ProvidePlugin and externals seem to be related to this (so is bundle! loader somewhere) but I cannot figure out when to use which. Thanks 回答1: It's both possible

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: i read the requirejs document from here api requirejs.config({ shim: { 'backbone': { //These script dependencies should be loaded before loading //backbone.js deps: ['underscore', 'jquery'], //Once loaded, use the global 'Backbone' as the //module value. exports: 'Backbone' }, 'underscore': { exports: '_' }, 'foo': { deps: ['bar'], exports: 'Foo', init: function (bar) { //Using a function allows you to call noConflict for //libraries that support it, and do other cleanup. //However, plugins for those libraries may still want //a global.

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I have seen variables like _ image and was wondering what _ meant? 回答1: It doesn't mean anything. It is rather a common naming convention for private member variables to keep them separated from methods and public properties. For example: class Foo { private int _counter; public int GetCounter() { return _counter; } public int SetCounter(int counter) { _counter = counter; } } 回答2: In most languages _ is the only character allowed in variable names besides letters and numbers. Here are some common use cases: Separating words: some_variable

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I have such a piece of code from this question : def addChild(n: Node, newChild: Node) = n match { case Elem(prefix, label, attribs, scope, child @ _*) => Elem(prefix, label, attribs, scope, child ++ newChild : _*) case _ => error("Can only add children to elements!") } Everything in it is pretty clear, except this piece: child ++ newChild : _* What does it do? I under stand there is Seq[Node] concatenated with another Node, and then? What does : _* do? 回答1: It "splats" 1 the sequence. Look at the constructor signature new Elem(prefix:

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: What is the meaning of _ after for in this code? if tbh.bag: n = 0 for _ in tbh.bag.atom_set(): n += 1 回答1: _ has 3 main conventional uses in Python: To hold the result of the last executed expression(/statement) in an interactive interpreter session. This precedent was set by the standard CPython interpreter, and other interpreters have followed suit For translation lookup in i18n (see the gettext documentation for example), as in code like: raise forms.ValidationError(_("Please enter a correct username")) As a general purpose "throwaway"

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I am using a jQuery based WordPress Twitter widget and receive the error " ReferenceError: _ is not defined ". Am not sure how to declare the variable "_". Here is the widget: ' ); } document.getElementById('twitter_update_list_ ').innerHTML = statusHTML.join(''); var template = '\ \ \ \ \ '; jQuery( _.template( template, { user: twitters[0].user } )).insertAfter('.bizsteam_twitter ul'); } function relative_time(time_value) { var values = time_value.split( " " ); time_value = values[1] + " " + values[2] + ", " + values[5] + " " + values[3];

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I am trying to understand when a developer needs to define a C variable with preceding '_'. What is the reason for it? For example: uint32_t __xyz_ = 0; 回答1: Maybe this helps, from C99, 7.1.3 ("Reserved Identifiers"): All identifiers that begin with an underscore and either an uppercase letter or another underscore are always reserved for any use. All identifiers that begin with an underscore are always reserved for use as identifiers with file scope in both the ordinary and tag name spaces. Moral: For ordinary user code, it's probably best

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Today I see that - python add _$CLASSNAME$ to methods with name with __ . Simple example: >>> class A: ... def a(self): ... self.b() ... def b(self): ... print('A.b') ... >>> class B(A): ... def b(self): ... print('B.b') ... >>> B().a() B.b That work, but: >>> class A: ... def a(self): ... self.__b() ... def __b(self): ... print('A.b') ... >>> class B(A): ... def __b(self): ... print('B.b') ... >>> B().a() A.b Why? I don't know, so I dir'ed it. Here it is: >>> print([fn for fn in dir(B) if fn[-2:] != '__']) ['_A__b', '_B__b', 'a'] Why python