Python: Builds a list, using an iterator function and an initial seed value
Python List: Exercise - 219 with Solution
Write a Python program to build a list, using an iterator function and an initial seed value.
- The iterator function accepts one argument (seed) and must always return a list with two elements ([value, nextSeed]) or False to terminate.
- Use a generator function, fn_generator, that uses a while loop to call the iterator function and yield the value until it returns False.
- Use a list comprehension to return the list that is produced by the generator, using the iterator function.
def unfold(fn, seed): def fn_generator(val): while True: val = fn(val) if val == False: break yield val return [i for i in fn_generator([None, seed])] f = lambda n: False if n > 40 else [-n, n + 10] print(unfold(f, 10))
[-10, -20, -30, -40]
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Next: Write a Python program to map the values of a list to a dictionary using a function, where the key-value pairs consist of the original value as the key and the result of the function as the value.
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Python: Tips of the Day
When we speak of division we normally mean (/) float division operator, this will give a precise result in float format with decimals.
For a rounded integer result there is (//) floor division operator in Python. Floor division will only give integer results that are round numbers.
print(1000 // 300) print(1000 / 300)
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