Generators as pipes

gistfile1.py

def peak_to_peak(iterable):
    """
    From an input iterable find the present maximum range. Only yield when the range gets larger
    """
    it = iter(iterable)
    first_value = it.next()
    the_min = first_value
    the_max = first_value
    while True:
        value = it.next()
        if value < the_min:
            the_min = value
            yield the_max - the_min      # Only yield when peak changed
        elif value > the_max:
            the_max = value
            yield the_max - the_min      # Only yield when peak changed


import random
def randoms():
    while True:
        yield random.random()    # Just get some random numbers


# Application with finite list
for peak in peak_to_peak([1, 2, 3, 5, -5, 3, 3, 8, 10, 100, 1, 1]):
    print(peak)


# Application with infinite "list"
for peak in peak_to_peak(randoms()):
    print(peak)



# Another "pipe"
def stop_at(iterable, limit=10):
    it = iter(iterable)
    while True:
       value = it.next()
       yield value
       if value > limit:
           break


def randoms():
    """Gaussian distributed variables"""
    while True:
        yield random.normalvariate(0, 1)    


for peak in stop_at(peak_to_peak(randoms()), 10.5): 
    print(peak)