alg_sequential_search.py

from __future__ import absolute_import
from __future__ import print_function
from __future__ import division


def sequential_search(a_list, item):
    """Sequential search by iteration."""
    pos = 0
    is_found = False
    while pos < len(a_list) and not is_found:
        if a_list[pos] == item:
            is_found = True
        else:
            pos += 1
    return is_found


def sequential_search_ordered(a_list, item):
    """Sequential search by ordering first."""
    a_list = sorted(a_list)
    pos = 0
    is_found = False
    is_stop = False
    while pos < len(a_list) and not is_found and not is_stop:
        if a_list[pos] == item:
            is_found = True
        else:
            if a_list[pos] > item:
                is_stop = True
            else:
                pos += 1
    return is_found


def main():
    import time
    a_list = [54, 26, 93, 17,77, 31, 44, 55, 20, 65]

    start_time = time.time()
    item = 65
    print('Search item {0}: {1}'
          .format(item, sequential_search(a_list, item)))
    item = 100
    print('Search item {0}: {1}'
          .format(item, sequential_search(a_list, item)))
    print('Time for sequential sorts: {}'
          .format(time.time() - start_time))

    start_time = time.time()
    item = 65
    print('Search item {0}: {1}'
          .format(item, sequential_search_ordered(a_list, item)))
    item = 100
    print('Search item {0}: {1}'
          .format(item, sequential_search_ordered(a_list, item)))
    print('Time for sequential sort ordered: {}'
          .format(time.time() - start_time))


if __name__ == '__main__':
    main()