Tukukkk

Here is the code which I used to find the third largest element in the list without using any built in functions like max,sort,len.

list = [12, 45, 2, 41, 31, 10, 8, 6, 4]

#list = [35,10,45,9,8,5]

largest_1 = list[0]

largest_2 = list[0]

largest_3 = list[0]

print (largest_1)

print (largest_2)

print (largest_3)

for each in list:

    print ('Each element Before if Loop --->',each)

    if each > largest_1:

        print ('Each element inside if loop --->',each)

        largest_1 = each

        print('largest_1 element---->',largest_1)

    elif largest_2 != largest_1 and largest_2 < each:

        print ('Each element inside if loop --->',each)

        largest_2 = each 

        print ('Largest_1 element is ---->',largest_1)

        print ('Largest_2 element is ---->',largest_2)

    elif largest_3 != largest_2  and largest_3 < each:

        print ('Each element inside if loop --->',each)

        largest_3 = each

        print ('Largest_2 element is ---->',largest_2)

        print ('Largest_3 element is ---->',largest_3)



print (largest_1)

print (largest_2)

print (largest_3)

The same code is not working for the

list = [35,10,45,9,8,5]

I am not getting what mistake I have done. How can I fix this?

I don't know why you wouldn't want to use len(), or max() - they're literally built-in functions, not part of any library, and there's no practical reason not to use them. That said, if you really want to do it otherwise, here's another approach:

Take three variables, assign them largest, second_largest, and third_largest, and walk through the list.

largest = 0

second_largest = 0

third_largest = 0



for each in list:

    if each >= largest:

        # assign the new largest, and push the rest of them back down the chain

        # we use >= instead of > to ensure that duplicate maximums still work.

        #   

        largest, second_largest, third_largest = each, largest, second_largest

    elif each >= second_largest:

        second_largest, third_largest = each, second_largest

    elif each > third_largest:

        third_largest = each

print(third_largest)

@venkat: Here another proposal to get the third largest number out of your list without using len() and sort().

def find_largest(alist):

    """

    Find the largest number in a list.



    Return the largest number found and it index

    """

    largest = alist[0]

    for item in alist[1:]:

        if item > largest:

            largest = item



    idx =  alist.index(largest)

    return (idx, largest)



#--

def get_third_largest(alist):

    """

    Return the third largest number in a list.

    """

    # Let make a copy of the input list so that any change to it may not affect the

    # original data.

    thisList = alist.copy()



    index, largest = 0, 0

    for item in range(3):

        index, largest = find_largest(thisList)

        if item != 2:

            # delete the first two largest from the List

            del thisList[index]

    return largest



# Test of the algorithm

if __name__ == "__main__":

    List = [12, 45, 2, 41, 31, 10, 8, 6, 4]

    third = get_third_largest(List)

    # print("Initial list: ", List)

    # print("The third largest item in the list:")

    print("tExpected: 31")

    print("tResult:   %d" % third);



# --- Output---

# Expected: 31

# Result:   31

You could also store your top 3 max numbers in a dictionary, then print out the third largest one:

largest = {"first": 0, "second": 0, "third": 0}



lst = [12, 45, 2, 41, 31, 10, 8, 6, 4]



for number in lst:

    if number > largest["first"]:

        largest["third"] = largest["second"]

        largest["second"] = largest["first"]

        largest["first"] = number

    elif number > largest["second"]:

        largest["third"] = largest["second"]

        largest["second"] = number

    elif number > largest["third"]:

        largest["third"] = number



print(largest)

# {'first': 45, 'second': 41, 'third': 31}



print(largest["third"])

# 31