如何更改此函数调用和算法，以在大小为n的列表中找到值最小的字符串。 没有最小功能

Question

How can I change this function call and algorithm to find the string with the smallest value in a list with size n. Also I am aware of the built-in min function, I am simply trying to understand the mechanics. Let me also preface this by saying I am a first semester CS student, so I apologize in advance for my ignorance.

def main():


    strOne = 'stack'
    strTwo = 'over'
    strThree = 'flow'
    strFour = 'please'
    strFive = 'help'

    first = alphabetical(strOne, strTwo, strThree, strFour, strFive)

    print(first)

def alphabetical(one, two, three, four, five):
    low = one
    if two < low:
        low = two
    if three < low:
        low = three
    if four < low:
        low = four
    if five < low:
        low = five  
    return low

main()

    ###################################################################      
    # str_list = ['stack', 'over', 'flow', 'please', 'help'] ??       #
    # for i in str_list: ?? perhaps on the right track with this idea.#
    #       first = alphabetical(i) ?? maybe                          #  
    ###################################################################

Answer 1

Using sort does too many comparisons. To emulate what min does, you should make just a single pass over the data, updating the best (lowest) value seen so far.

>>> def lowest(sequence):
        'Find the lowest value in a sequence in just one-pass'
        best = sequence[0]
        for i in range(1, len(sequence)):
            if sequence[i] < best:
                best = sequence[i]
        return best

>>> lowest(['stack', 'over', 'flow', 'please', 'help'])
'flow'

Answer 2

list.sort() will sort a list in-place. Element [0] is first element in a list. This should be everything needed to accomplish what you're doing, without a fixed-parameter function.

Playing around in the python interactive shell:

>>> l = ['stack', 'over', 'flow']
>>>
>>> l.sort()
>>>
>>> l
['flow', 'over', 'stack']
>>> l[0]
'flow'

A program

def main():
    str_list = ['stack', 'over', 'flow', 'please', 'help']

    str_list.sort()    # Doesn't return anything; sorts the list in-place.

    print 'First string:', str_list[0]

if __name__ == '__main__':
    main()

Answer 3

You can use the built-in function min:

>>> min('stack', 'over', 'flow', 'please', 'help')
   'flow'