A correct, efficient answer written as a generator. import os def reverse_readline(filename, buf_size=8192): “””A generator that returns the lines of a file in reverse order””” with open(filename) as fh: segment = None offset = 0 fh.seek(0, os.SEEK_END) file_size = remaining_size = fh.tell() while remaining_size > 0: offset = min(file_size, offset + buf_size) fh.seek(file_size – offset) … Read more
The Collections.reverse method actually returns a new list with the elements of the original list copied into it in reverse order, so this has O(n) performance with regards to the size of the original list. As a more efficient solution, you could write a decorator that presents a reversed view of a List as an … Read more
#include <algorithm> std::reverse(str.begin(), str.end()); This is the simplest way in C++.
data.reindex(index=data.index[::-1]) or simply: data.iloc[::-1] will reverse your data frame, if you want to have a for loop which goes from down to up you may do: for idx in reversed(data.index): print(idx, data.loc[idx, ‘Even’], data.loc[idx, ‘Odd’]) or for idx in reversed(data.index): print(idx, data.Even[idx], data.Odd[idx]) You are getting an error because reversed first calls data.__len__() which returns … Read more
I would suggest using a custom filter such as this: app.filter(‘reverse’, function() { return function(items) { return items.slice().reverse(); }; }); Which can then be used like: <div ng-repeat=”friend in friends | reverse”>{{friend.name}}</div> See it working here: Plunker Demonstration This filter can be customized to fit your needs as seen fit. I have provided other examples … Read more
Use the .clone() method on your List. It will return a shallow copy, meaning that it will contain pointers to the same objects, so you won’t have to copy the list. Then just use Collections. Ergo, Collections.reverse(list.clone()); If you are using a List and don’t have access to clone() you can use subList(): List<?> shallowCopy … Read more
This will give you a sorted version of the array. sorted(timestamps, reverse=True) If you want to sort in-place: timestamps.sort(reverse=True) Check the docs at Sorting HOW TO
$($(“li”).get().reverse()).each(function() { /* … */ });
use reversed() function: reversed(range(10)) It’s much more meaningful. Update: If you want it to be a list (as btk pointed out): list(reversed(range(10))) Update: If you want to use only range to achieve the same result, you can use all its parameters. range(start, stop, step) For example, to generate a list [5,4,3,2,1,0], you can use the … Read more
As long as you’re dealing with simple ASCII characters, and you’re happy to use built-in functions, this will work: function reverse(s){ return s.split(“”).reverse().join(“”); } If you need a solution that supports UTF-16 or other multi-byte characters, be aware that this function will give invalid unicode strings, or valid strings that look funny. You might want … Read more