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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: So I'll break my question into 4 parts, but first some background: I feel relatively comfortable with Monads, but not very comfortable with Arrows. I suppose the main problem I have with them is, I don't see what they are useful for. Whether formally correct or not, I understand Monads to be a tool that allows us to introduce side effects from computation. As they generalize program fragments from pure values to values boxed with other actions. From my shotgun "read all the papers" approach to learning about arrows, I've come across two

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: The title says it all. When I call the mDrawerToggle.setDrawerIndicatorEnabled(false) I don't want the " hamburger " icon to be shown anymore but the backwards navigation arrow. Unfortunately when I call this method just the title is shown without the backwards arrow nor the "hamburger" icon. After setting the drawerIndicatorEnabled to be true again it shows the "hamburger" icon again. I set getSupportActionBar().setDisplayHomeAsUpEnabled(true) and getSupportActionBar().setDisplayShowHomeEnabled(true) Edit: Basically the solution suggested

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: Im using foloowing code to track key events oEvent=window.event || oEvent; iKeyCode=oEvent.keyCode || oEvent.which;alert(iKeyCode); its giving me alerts in firefox but not in IE and chrome. Its giving me all the other keyborad characters but not esc key and arrow keys. How can i detect esc key and arrow keys in chrome and IE using javascript?? 回答1: You don't really need JQuery, though it does make your code shorter. You will have to use the keyDown event, keyPress will not work in old versions of IE for the arrow keys. There is a full

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: This question already has an answer here: Methods in ES6 objects: using arrow functions 3 answers I'm trying out ES6 and want to include a property inside my function like so var person = { name: "jason", shout: () => console.log("my name is ", this.name) } person.shout() // Should print out my name is jason However, when I run this code console only logs my name is . What am I doing wrong? 回答1: Short answer: this points at the nearest bound this - in the code provided this is found in the enclosing scope. Longer answer: Arrow functions bind

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): 由 翻译 强力驱动 问题: Using ES6 arrow functions with lexical this binding is great. However, I ran into an issue a moment ago using it with a typical jQuery click binding: class Game { foo () { self = this ; this . _pads . on ( 'click' , function () { if ( self . go ) { $ ( this ). addClass ( 'active' ); } }); } } Using an arrow function instead: class Game { foo () { this . _pads . on ( 'click' , () => { if ( this . go ) { $ ( this ). addClass ( 'active' ); } }); } } And then $(this) gets converted to ES5 (self = this) type closure. Is a way to have

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 currently learning C by reading a good beginner's book called "Teach Yourself C in 21 Days" (I have already learned Java and C# so I am moving at a much faster pace). I was reading the chapter on pointers and the -> (arrow) operator came up without explanation. I think that it is used to call members and functions (like the equivalent of the . (dot) operator, but for pointers instead of members). But I am not entirely sure. Could I please get an explanation and a code sample? 回答1: foo->bar is equivalent to (*foo).bar , i.e. it gets the

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 trying to wrap my head around how Haskell's Control.Arrow 's &&& works, but fear I'm on the verge of losing my way. Specifically, I'm confused (as a beginner) by how to makes sense of its behavior from the type signature (&&&) :: a b c -> a b c' -> a b (c, c') in import Control.Arrow (negate &&& (+5)) [1,2,3] or even just (negate &&& (+5)) 5 for example, the first argument is "missing" b and c , while the second is missing just c' , and the result looks to me like (c, c') , not a b (c, c') . Can someone walk me through how &&& works, in

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 trying to wrap my head around how Haskell's Control.Arrow 's &&& works, but fear I'm on the verge of losing my way. Specifically, I'm confused (as a beginner) by how to makes sense of its behavior from the type signature (&&&) :: a b c -> a b c' -> a b (c, c') in import Control.Arrow (negate &&& (+5)) [1,2,3] or even just (negate &&& (+5)) 5 for example, the first argument is "missing" b and c , while the second is missing just c' , and the result looks to me like (c, c') , not a b (c, c') . Can someone walk me through how &&& works, in

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 use pyplot.arrow do draw some straight arrows, e.g., import matplotlib.pyplot as plt import numpy as np v={} for i in range (1,4): v[i]=np.array([np.cos(-2*np.pi/3*i),np.sin(-2*np.pi/3*i)]) plt.arrow(.85*(.05*v[2]+.95*v[1])[0],.85*(.05*v[2]+.95*v[1])[1],.85*.9*(v[2]-v[1])[0],.85*.9*(v[2]-v[1])[1],width=0,head_width=.03,head_length=.045,length_includes_head=True,color="black") plt.arrow(.85*(.05*v[3]+.95*v[2])[0],.85*(.05*v[3]+.95*v[2])[1],.85*.9*(v[3]-v[2])[0],.85*.9*(v[3]-v[2])[1],width=0,head_width=.03,head_length=.045,length_includes

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 want to make a button for my shape like this one Is there a way to do this with xml ? Like setting some points, in my case I have 5.. 回答1: What you need is to create a shape xml file in your project's drawable-xxx folder and then use this shape as background for a button. Here is the shape file called arrow_shape.xml : Then use it as button's background, for example Here is the screenshot: More info on Layer-List you can find here . EDIT: Keep in mind though that I used certain values for the shape's width and height. If you change those