concatenation

问题 I'm surprised there's not an overload that can take a string array. Anyway, what is the best way to avoid nesting calls to Path.Combine? pathValue = Path.Combine(path1, Path.Combine(path2, Path.Combine(path3, path4))) This seems inefficient since it results in four new strings being created just to get one. 回答1: The efficiency side of things isn't the problem IMO - it's the usability side of things. Personally I think there ought to be an overload of: Combine(string first, string second,

问题 I have finished a homework assignment for my programming class. I was supposed to create a Prolog program that reverses a list. I, however, am having trouble understanding why exactly it works. %1. reverse a list %[a,b,c]->[c,b,a] %reverse(list, rev_List). reverse([],[]). %reverse of empty is empty - base case reverse([H|T], RevList):- reverse(T, RevT), conc(RevT, [H], RevList). %concatenation What exactly is RevT in this case? I know it is supposed to represent the reverse of T or the rest

问题 I have finished a homework assignment for my programming class. I was supposed to create a Prolog program that reverses a list. I, however, am having trouble understanding why exactly it works. %1. reverse a list %[a,b,c]->[c,b,a] %reverse(list, rev_List). reverse([],[]). %reverse of empty is empty - base case reverse([H|T], RevList):- reverse(T, RevT), conc(RevT, [H], RevList). %concatenation What exactly is RevT in this case? I know it is supposed to represent the reverse of T or the rest

问题 While I can successfully encode and decode the user data part of an SMS message when a UDH is not present, I'm having trouble doing so when a UDH is present (in this case, for concatenated SMS). When I decode or encode the user data, do I need to prepend the UDH to the text before doing so? This article provides an encoding routine sample that compensates for the UDH with padding bits (which I still don't completely understand) but it doesn't give an example of data being passed to the

问题 Given an arbitrary list of column names in a data.table , I want to concatenate the contents of those columns into a single string stored in a new column. The columns I need to concatenate are not always the same, so I need to generate the expression to do so on the fly. I have a sneaking suspicion that way I'm using the eval(parse(...)) call could be replaced with something a bit more elegant, but the method below is the fastest I've been able to get it so far. With 10 million rows, this

问题 I am trying to merge css and scss files into a main.css file that goes in my build directory. Its working, but not in the right order. The style attributes from the scss files need to be in the bottom of the main.css file so they overrule the rest. my Gulp task looks like this: //CSS gulp.task('css', function () { var cssTomincss = gulp.src(['dev/css/reset.css', 'dev/css/style.css','dev/css/typography.css', 'dev/css/sizes.css']); var cssFromscss = gulp.src(['dev/css/*.scss']) .pipe(sass());

问题 This question already has answers here : Reproduce the Unix cat command in Python (6 answers) Closed 6 years ago . Is there a way to use the cat function from Unix in Python or something similar once a directory has been established ? I want to merge files_1-3 together into merged.txt I would usually just find the directory in Unix and then run cat * > merged.txt file_1.txt file_2.txt file_3.txt merged.txt 回答1: As we know we are going to use "Unix" cat command (unless you are looking for a

问题 I am developing an application. People upload videos from their mobile, from other places. Using a CMS in PHP (it is the language with which the application is developed) I need to generate a unique video with these partial uploads. Through FFmpeg I am doing tests, from the command line: ffmpeg -i concat:IMG_1916.mp4\|IMG_1917.mp4 -c copy videoLoop.mp4 This code when I run it says: ffmpeg version 3.2.4 Copyright (c) 2000-2017 the FFmpeg developers built with Apple LLVM version 8.0.0 (clang

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 4 years ago . Could anybody help me with the php code for FFMPEG to concatenate two mp4 videos and store the concatenated files as an mp4 at any folder in the server? 回答1: For the FFMPEG part see here: Concatenate two mp4 files using ffmpeg For the PHP part, you can invoke any command using:

问题 I am trying to use the ConcatRelated function to provide a summary report of the prior day's absences, tardies, and vacations. I have tried several variations and can't seem to get it to work in an Access Query. My table looks as below: ID A_date Area ATV_Shift Associate_Name Absent Tardy Vacation Reason -- --------- ----------- --------- -------------- ------ ----- -------- -------------- 1 1/11/2015 Asm Kenmore First Keon Wilson 1 Sick 2 1/11/2015 Asm Kenmore First Frank Burns 1 Doctor 3 1