循环将测试结果存储在Python中

Question

In short, I need to test some functions by creating 100 random integer lists of each specified length (500, 1000, 10000) and store the results. Eventually, I need to be able to calculate an average execution time for each test but I've yet to get that far with the code.

I assumed the following was the best way to approach this:

1. Create a dictionary to store the required list length values.
2. For each value in that dictionary, generate a new list of random integers (list_tests).
3. Create another dictionary for storing the results of each function test (test_results).
4. Use a while loop to create 100 lists of each length.
5. Run the tests by calling each function in the while loop and storing each result in the results dictionary.

The program appears to run but I have a couple problems:

• It never reaches the other list_tests values; never proceeds beyond 500.
• It's overwriting the values for the test_results dictionary

I don't quite understand where I've gone wrong with the loop in main(). Is my process to test these functions feasible? If so, I'm lost as to how I can fix this looping problem. Thank you in advance for any assistance you can offer!

Here is my program:

import time
import random


def sequential_search(a_list, item):
    start = time.time()
    pos = 0
    found = False

    while pos < len(a_list) and not found:
        if a_list[pos] == item:
            found = True
        else:
            pos = pos+1

    end = time.time()

    return found, end-start


def ordered_sequential_search(a_list, item):
    start = time.time()
    pos = 0
    found = False
    stop = False

    while pos < len(a_list) and not found and not stop:
        if a_list[pos] == item:
            found == True
        else:
            if a_list[pos] > item:
                stop = True
    else:
        pos = pos+1

    end = time.time()

    return found, end-start


def num_gen(value):
    myrandom = random.sample(xrange(0, value), value)
    return myrandom


def main():
    #new_list = num_gen(10000)
    #print(sequential_search(new_list, -1))

    list_tests = {'t500': 500, 't1000': 1000, 't10000': 10000}

    for i in list_tests.values():
        new_list = num_gen(i)
        count = 0
        test_results = {'seq': 0, 'ordseq': 0}
        while count < 100:
            test_results['seq'] += sequential_search(new_list, -1)[1]
            test_results['ordseq'] += ordered_sequential_search(new_list, -1)[1]
            count += 1


if __name__ == '__main__':
    main()

Answer 1

I think you meant

found = True

Instead of

found == True

On line 47

Also a for loop is much cleaner try this, it should be what your looking for:

def ordered_sequential_search(a_list, item):
    start = time.time()
    found = False
    stop = False

    for i in range(len(a_list)):
        if a_list[i] == item:
            found = True
        else:
            if a_list[i] > item:
                stop = True
        if found: break
        if stop: break

    end = time.time()

    return found, end-start

Answer 2

It is overwriting values in the dictionary because you have specified the key to overwrite values. You are not appending to the dictionary which you should have done.

Your while loop might not be breaking, that why your for loop cannot iterate to another value.