reverse

I am working with audio data. I'd like to play the sample file in reverse. The data is stored as unsigned ints and packed nice and tight. Is there a way to call memcpy that will copy in reverse order. i.e. if I had 1,2,3,4 stored in an array, could I call memcpy and magically reverse them so I get 4,3,2,1. This works for copying int s in reverse: void reverse_intcpy(int *restrict dst, const int *restrict src, size_t n) { size_t i; for (i=0; i < n; ++i) dst[n-1-i] = src[i]; } Just like memcpy() , the regions pointed-to by dst and src must not overlap. If you want to reverse in-place: void

What is typically regarded as more Pythonic/better/faster to use, the reverse method or the reversed built-in function? Both in action: _list = list(xrange(4)) print _list rlist = list(reversed(_list)) print rlist _list.reverse() print _list Depends on whether you want to reverse the list in-place (i.e. change the list) or not. No other real difference. Often using reversed leads to nicer code. foo.reverse() actually reverses the elements in the container. reversed() doesn't actually reverse anything, it merely returns an object that can be used to iterate over the container's elements in

I'm writing a small shell script that needs to reverse the lines of a text file. Is there a standard filter command to do this sort of thing? My specific application is that I'm getting a list of Git commit identifiers, and I want to process them in reverse order: git log --pretty=oneline work...master | grep -v DEBUG: | cut -d' ' -f1 | reverse The best I've come up with is to implement reverse like this: ... | cat -b | sort -rn | cut -f2- This uses cat to number every line, then sort to sort them in descending numeric order (which ends up reversing the whole file), then cut to remove the

I want to simply reverse the column order of a given DataFrame. My DataFrame: data = {'year': [2010, 2011, 2012, 2011, 2012, 2010, 2011, 2012], 'team': ['Bears', 'Bears', 'Bears', 'Packers', 'Packers', 'Lions', 'Lions', 'Lions'], 'wins': [11, 8, 10, 15, 11, 6, 10, 4], 'losses': [5, 8, 6, 1, 5, 10, 6, 12]} football = pd.DataFrame(data, columns=['year', 'team', 'wins', 'losses']) Actual output: year team wins losses 0 2010 Bears 11 5 1 2011 Bears 8 8 2 2012 Bears 10 6 3 2011 Packers 15 1 4 2012 Packers 11 5 5 2010 Lions 6 10 6 2011 Lions 10 6 7 2012 Lions 4 12 I thought this would work but it

I was able to reverse with: ffmpeg -i input.mp4 -vf reverse output_reversed.mp4 And I can concat with: ffmpeg -i input.mp4 -i input.mp4 -filter_complex "[0:0] [0:1] [1:0] [1:1] concat=n=2:v=1:a=1 [v] [a]" -map "[v]" -map "[a]" output.mp4 But can I concat with a reverse version of the video, with a single command? What I am trying to achieve is a ping pong effect, where the video plays once, then plays backwards right after. Thanks! Gyan Technically, you can do it using ffmpeg -i input.mp4 -filter_complex "[0:v]reverse,fifo[r];[0:v][0:a][r] [0:a]concat=n=2:v=1:a=1 [v] [a]" -map "[v]" -map "[a]"

I'm using django-cms with apphooks to display book detail information. I need the page with the app hook to accept a slug that specifies which book to display. I created a page called 'books' and added the apphook 'BookDetailApp'. Here's what my books.cms_app file looks like: class BooksApp (CMSApp): name = _('Book Detail Page Application') urls = ['books.urls'] apphook_pool.register(BooksApp) Here's what my books.urls looks like: urlpatterns = patterns('', url(r'^(?P<slug>[\w\-]+)?', BookDetailView.as_view(), name='book_detail'), ) And here's what my books.views file looks like: class