python function pipeline

Python Function Pipeline

In this article, we show how to use "Map & Reduce, not loop" to implement function pipeline in python

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def even_filter(nums):     return filter(lambda x: x%2==0, nums)   def multiply_by_three(nums):     return map(lambda x: x*3, nums)   def convert_to_string(nums):     return map(lambda x: 'The Number: %s' % x,  nums)   nums = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] pipeline = convert_to_string(                multiply_by_three(                    even_filter(nums)                )             ) for num in pipeline:     print num

In the above code, you have to use nested functions to achieve the goal, which is kinda clunky. Actually, a more natural way is as following. 

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pipeline_func(nums, [even_filter,                      multiply_by_three,                      convert_to_string])

Here is how we implents pipeline_func: 

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def pipeline_func(data, fns):     return reduce(lambda a, x: x(a),                   fns,                   data)