each

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 some data that looks like the following. It is grouped by variable "Year" and I want to extract the percentiles of each observation of Score, with respect to the Year it is from, preferably as a vector. Year Score 2001 89 2001 70 2001 72 2001 ... .......... 2004 87 2004 90 etc. How can I do this? aggregate will not work, and I do not think apply will work either. 回答1: Following up on Vince's solution, you can also do this with plyr or by : ddply(df, .(years), function(x) transform(x, percentile=ecdf(x$scores)(x$scores))) 回答2: Using

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 an array of strings, and want to make a hash out of it. Each element of the array will be the key, and I want to make the value being computed from that key. Is there a Ruby way of doing this? For example: ['a','b'] to convert to {'a'=>'A','b'=>'B'} 回答1: You can: a = ['a', 'b'] Hash[a.map {|v| [v,v.upcase]}] 回答2: %w{a b c}.reduce({}){|a,v| a[v] = v.upcase; a} 回答3: Here's a naive and simple solution that converts the current character to a symbol to be used as the key. And just for fun it capitalizes the value. :) h = Hash.new ['a', 'b

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: I found this famous dp problem in many places, but I can not figure out how to solve. You are given a set of n types of rectangular 3-D boxes, where the i^th box has height h(i), width w(i) and depth d(i) (all real numbers). You want to create a stack of boxes which is as tall as possible, but you can only stack a box on top of another box if the dimensions of the 2-D base of the lower box are each strictly larger than those of the 2-D base of the higher box. Of course, you can rotate a box so that any side functions as its base.

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: $('elems').each() with fat arrow 2 answers I have this ES6 code, after I compile it with Babel to ES5 the this inside .each 's call back becomes undefined . How do I fix this problem? let mediaBoxes = $(".now-thumbnail"); let titles = []; mediaBoxes.each(() => { let obj = { index: i, title: $(this).find(".now-thumbnail-bottomtext").text().trim() }; titles.push(obj); }); 回答1: My solution is to not use this at all, but use the variables that are passed to the callback function. The first one is 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: Is there a way to get the font of each line of a PDF file using PDFBox? I have tried this but it just lists all the fonts used in that page. It does not show what line or text is showed in that font. List pages = doc.getDocumentCatalog().getAllPages(); for(PDPage page:pages) { Map pageFonts=page.getResources().getFonts(); for(String key : pageFonts.keySet()) { System.out.println(key+" - "+pageFonts.get(key)); System.out.println(pageFonts.get(key).getBaseFont()); } } Any input is appreciated. Thanks! 回答1: Whenever you try to extract text

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 an assortment of similar (but not identical) databases, and would like to use SQLAlchemy as a way to "standardize" access. The databases can differ very slightly, such as having a unique prefix on the column names, or they can differ more dramatically and be missing columns (or for old databases, missing entire tables). What I'm looking for help on isn't so much an SQLAlchemy problem as it is a Python/Organizational one. How can I have multiple databases setup that can be reused in projects easily? I've read about SQLAlchemy sessions,

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 cat *.txt to merge multiple txt files into one, but I need each file to be on a separate line. What is the best way to merge files with each file appearing on a new line? 回答1: just use awk awk 'FNR==1{print ""}1' *.txt 回答2: If you have a paste that supports it, paste --delimiter=\\n --serial *.txt does a really great job 回答3: You can iterate through each file with a for loop: for filename in *.txt; do # each time through the loop, ${filename} will hold the name # of the next *.txt file. You can then arbitrarily process # each file

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: For Fibers we have got classic example: generating of Fibonacci numbers fib = Fiber.new do x, y = 0, 1 loop do Fiber.yield y x,y = y,x+y end end Why do we need Fibers here? I can rewrite this with just the same Proc (closure, actually) def clsr x, y = 0, 1 Proc.new do x, y = y, x + y x end end So 10.times { puts fib.resume } and prc = clsr 10.times { puts prc.call } will return just the same result. So what are the advantages of fibers. What kind of stuff I can write with Fibers I can't do with lambdas and other cool Ruby features? 回答1:

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: Can anyone explain the differences, in IIS, between application pools, worker processes and app domains? Also, how do they work together? I've read a couple of articles but it's still a little confusing. Does each website created in IIS becomes an application? Is each application associated with one worker process? Where do app domains come into the picture? 回答1: I try to say them with other words. In a server you can have many asp.net sites that runs together. Each one site is an app domain . You must assign to each of them one application

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: This question already has an answer here: Why does the first panel added to a frame disappear? 2 answers public class Board extends JFrame { public void bd () { JFrame frame = new JFrame (); JLabel background1 = new JLabel ( new ImageIcon ( "background.png" )); JLabel knight = new JLabel ( new ImageIcon ( "knight.jpg" )); frame . add ( background1 ); frame . add ( knight ); frame . pack (); frame . setResizable ( false ); frame . setVisible ( true ); } } I've been having some trouble with my code when i add the knight image the