(unorderd and orderd) linear/sequential search implemented with python lists: http://interactivepython.org/runestone/static/pythonds/SortSearch/TheSequentialSearch.html

orderedSequentialSearch.py

def orderedSequentialSearch(alist, item):
  '''
  O(n/2) in item is not present average case
  '''
	    pos = 0
	    found = False
	    stop = False
	    while pos < len(alist) and not found and not stop:
	        if alist[pos] == item:
	            found = True
	        else:
	            if alist[pos] > item:
	                stop = True
	            else:
	                pos = pos+1
	
	    return found
	
	testlist = [0, 1, 2, 8, 13, 17, 19, 32, 42,]
	print(orderedSequentialSearch(testlist, 3))
	print(orderedSequentialSearch(testlist, 13))

sequentialSearch.py

def sequentialSearch(alist, item):
    '''
  O(n) in item is not present average case
  '''
	    pos = 0
	    found = False
	
	    while pos < len(alist) and not found:
	        if alist[pos] == item:
	            found = True
	        else:
	            pos = pos+1
	
	    return found
	
testlist = [1, 2, 32, 8, 17, 19, 42, 13, 0]
print(sequentialSearch(testlist, 3))
print(sequentialSearch(testlist, 13))