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P: 27
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Hello all!
I have a variable name "thelist" which is a list of 100,000 elements. I was wondering how I can make two new lists of the average value and standard deviation from this. For example if my list is [1,2,3,4,5,6,7,8,9,10] then the new list would be the average of the every 5 numbers, endeing up looking like [average(1,2,3,4,5),average(6,7,8,9,10)]=[3,8]. I am very comfortable using numpy to get the average and standard deviation values. I am just having trouble breaking the initial list down. I'm not sure if this is what indexing is.
Any help would really be appreciated,
Thank YOU!
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P: 27
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I am also curious to know if there is a simple way to see how many positive numbers there are in each 100 segments of the bit 100,000 list. Thank YOU!
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| Expert 100+
P: 621
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For example if my list is [1,2,3,4,5,6,7,8,9,10] then the new list would be the average of the every 5 numbers
You can use two for loops. With the outer loop, set the step value at 5 or whatever the increment. The inner loop adds each of the 5 numbers together. - test_list = range(1, 51)
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for outer in range(0, len(test_list), 5):
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total = 0
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for inner in range(5):
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total += test_list[outer+inner]
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print test_list[outer+inner],
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print "\n", float(total)/5
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P: n/a
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omg, awful! - lambda lst, ln: [ lst[i:i+ln] for i in range(0, len(lst), ln) ]
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| Expert Mod 2.5K+
P: 2,851
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What's the lambda for? - >>> data = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]
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>>> n = 5
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>>> def average(seq):
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... return sum(seq)/float(len(seq))
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...
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>>> [average(data[i:i+n]) for i in range(0, len(data), n)]
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[3.0, 8.0, 13.0]
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>>> data = [1,2,-3,4,5,6,-7,8,-9,10,11,-12,-13,-14,15]
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>>> [sum([1 for item in data[i:i+n] if item>0]) for i in range(0, len(data), n)]
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[4, 3, 2]
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>>>
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- replies: 4
- date asked: Nov 24 '10
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