CODEWITHSUNDEEP
python
Kevvv
Kevvv

Reputation: 239

Compare integers by using for loop

I'm python newbie and got a problem while doing some practices.

Below is the code that I've got so far:

def gt(nums, n):
    for c in nums:
        if n < c:
            return True
        elif c < n:
            return False
        else:
            break

With above code, it does not return properly. The examples of correct answers here:

gt([1,2,3],3) => False
gt([1,2,3],2) => True

Upvotes: 0

Views: 1339

Answers (4)

perilbrain
perilbrain

Reputation: 8207

This could be better

def gt(nums, n):
    for c in nums:
       if n < c:
            return True

    return False

Upvotes: 0

Niklas B.
Niklas B.

Reputation: 95358

A simpler and more readable solution would be the following:

def gt(lst, n):
    return max(lst) > n

Upvotes: 7

Hugh Bothwell
Hugh Bothwell

Reputation: 56694

Long-ish response to Niklas B.'s comment:

I decided to test this, and here are the results. Blue dots are your function, green are Mario's; y axis is runtime in seconds, x axis is len(nums). enter image description here

As you said, both are O(n). Yours is faster up to about 45 items; for anything over 100 items, his is roughly twice as fast.

It's mostly irrelevant - this seems to be more of a beginner syntax question than anything else - and, as you say, Python isn't a speed demon to begin with. On the other hand, who doesn't like a bit more speed (so long as readability doesn't suffer)?

For those interested, here's the code I wrote to test this:

from random import randint
from timeit import Timer
import matplotlib.pyplot as plt

def gt1(nums, n):
    # based on Niklas B.'s answer - NOTE comparison is corrected
    return n < max(nums)

def gt2(nums, n):
    # based on Mario Fernandez's answer
    return any(e > n for e in nums)

def make_data(length, lo=0, hi=None):
    if hi is None:
        hi = lo + length - 1
    elif lo > hi:
        lo,hi = hi,lo
    return [randint(lo, hi) for i in xrange(length)]

def make_args(d):
    nums = make_data(d)
    n = randint(0,d)
    return "{}, {}".format(nums, n)

def time_functions(fns, domain, make_args, reps=10, number=10):
    fns = [fn.__name__ if callable(fn) else fn for fn in fns]
    data = [[] for fn in fns]
    for d in domain:
        for r in xrange(reps):
            args = make_args(d)
            for i,fn in enumerate(fns):
                timer = Timer(
                    setup='from __main__ import {}'.format(fn),
                    stmt='{}({})'.format(fn, make_args(d))
                )
                data[i].extend((d,res) for res in timer.repeat(number=number))
    return data

def plot_data(data, formats=None):
    fig = plt.figure()
    ax = fig.add_subplot(111)
    if formats is None:
        for d in data:
            ax.plot([x for x,y in d], [y for x,y in d])
    else:
        for d,f in zip(data, formats):
            ax.plot([x for x,y in d], [y for x,y in d], f)
    plt.show()

def main():
    data = time_functions([gt1, gt2], xrange(10, 501, 10), make_args)
    plot_data(data, ['bo', 'g.'])

if __name__=="__main__":
    main()

Upvotes: 1

Mario F
Mario F

Reputation: 47287

using a one liner

def gt(nums, n):
    return any(e > n for e in nums)

this breaks when the first element bigger than n is found.

Upvotes: 4

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