itertools

问题 There is an existing thread about this Zipping unequal lists in python in to a list which does not drop any element from longer list being zipped But it's not quite I'm after. Instead of returning None , I need it to copy the previous entry on the list. Is this possible? a = ["bottle","water","sky"] b = ["red", "blue"] for i in itertools.izip_longest(a,b): print i #result # ('bottle', 'red') # ('water', 'blue') # ('sky', None) # What I want on the third line is # ('sky', 'blue') 回答1:

问题 I have this code: from itertools import groupby from itertools import combinations teams = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] combo = list(combinations(teams, 2)) The output is a list of 45 tuples. [(1, 2), (1, 3), (1, 4), (1, 5), (1, 6), (1, 7), (1, 8), (1, 9), (1, 10), (2, 3), (2, 4), (2, 5), (2, 6), (2, 7), (2, 8), (2, 9), (2, 10), (3, 4), (3, 5), (3, 6), (3, 7), (3, 8), (3, 9), (3, 10), (4, 5), (4, 6), (4, 7), (4, 8), (4, 9), (4, 10), (5, 6), (5, 7), (5, 8), (5, 9), (5, 10), (6, 7), (6, 8),

问题 I know questions similar to this have been asked many, many times on Stack Overflow, but I need to remove duplicate tuples from a list, but not just if their elements match up, their elements have to be in the same order. In other words, (4,3,5) and (3,4,5) would both be present in the output, while if there were both (3,3,5) and (3,3,5) , only one would be in the output. Specifically, my code is: import itertools x = [1,1,1,2,2,2,3,3,3,4,4,5] y = [] for x in itertools.combinations(x,3): y

问题 I know questions similar to this have been asked many, many times on Stack Overflow, but I need to remove duplicate tuples from a list, but not just if their elements match up, their elements have to be in the same order. In other words, (4,3,5) and (3,4,5) would both be present in the output, while if there were both (3,3,5) and (3,3,5) , only one would be in the output. Specifically, my code is: import itertools x = [1,1,1,2,2,2,3,3,3,4,4,5] y = [] for x in itertools.combinations(x,3): y

问题 I know questions similar to this have been asked many, many times on Stack Overflow, but I need to remove duplicate tuples from a list, but not just if their elements match up, their elements have to be in the same order. In other words, (4,3,5) and (3,4,5) would both be present in the output, while if there were both (3,3,5) and (3,3,5) , only one would be in the output. Specifically, my code is: import itertools x = [1,1,1,2,2,2,3,3,3,4,4,5] y = [] for x in itertools.combinations(x,3): y

问题 I know questions similar to this have been asked many, many times on Stack Overflow, but I need to remove duplicate tuples from a list, but not just if their elements match up, their elements have to be in the same order. In other words, (4,3,5) and (3,4,5) would both be present in the output, while if there were both (3,3,5) and (3,3,5) , only one would be in the output. Specifically, my code is: import itertools x = [1,1,1,2,2,2,3,3,3,4,4,5] y = [] for x in itertools.combinations(x,3): y

问题 Closed . This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 5 years ago . Improve this question I have a list of items alist = ['dog', 'cat', 'fish'] I want to return all unique unordered pairs, so in this case: (dog,cat)(dog,fish)(fish,cat) itertools.combinations does not take into account the unordered condition, so it is not quite what I need. 回答1: Where is your

问题 I have the following function that I would like to run using multiprocessing: def bruteForcePaths3(paths, availableNodes): results = [] #start by taking each combination 2 at a time, then 3, etc for i in range(1,len(availableNodes)+1): print "combo number: %d" % i currentCombos = combinations(availableNodes, i) for combo in currentCombos: #get a fresh copy of paths for this combiniation currentPaths = list(paths) currentRemainingPaths = [] # print combo for node in combo: #determine better

问题 I asked a question yesterday and thanks to Tim Peters, it is solved. The question is here; itertools.product eliminating repeated elements The new question is further version of this. This time I will generate tuples inside of tuples. Here is an example; lis = [[(1,2), (3,4)], [(5,2), (1,2)], [(2,1), (1,2)]] When I use it in itertools.product function this is what I get, ((1, 2), (5, 2), (2, 1)) ((1, 2), (5, 2), (1, 2)) ((1, 2), (1, 2), (2, 1)) ((1, 2), (1, 2), (1, 2)) ((3, 4), (5, 2), (2, 1)

问题 The bounty expires in 4 days . Answers to this question are eligible for a +100 reputation bounty. Khawar Islam is looking for an answer from a reputable source . The identities list contains an big array of approximately 57000 images . Now, I am creating a negative list with the help of itertools.product() . This store the whole list in memory which is very costly and my system hanged after 4 minutes. How can i optimize the below code and avoid saving in memory?` for i in range(0, len