CODEWITHSUNDEEP
pythonduplicates
Sectah
Sectah

Reputation: 55

How to find a duplicate in a list without in-built functions in Python?

I'm trying to find if there is a duplicate within a list without using the in-built functions. So far I have something like this however it does not seem to be working. Can anyone help? Give pointers? Improvements? I'd appreciate it. (Python version 2.7.10)

def DupSearch(list):
counter=0
for i in range(len(list)):
    if list[i]==list[0]:
        for j in range(len(list)):
            if list[j]!=list[j+i]:
                print "No duplicated"
            else:
                counter=counter+1
                if counter == len(list):
                    print "Duplicate found"

DupSearch([1,2,3,4,5,3])

Upvotes: 0

Views: 4773

Answers (2)

Ahasanul Haque
Ahasanul Haque

Reputation: 11134

You can use a dictionary to store the frequency of individual element,

lst=[1,3,5,7,6]
dic={}

for i in lst:
    if i in dic.keys():
        dic[i]+=1
    else:
        dic[i]=1


duplicate= False

for key,value in dic.iteritems():
    if value>1:
        duplicate = True
        print "List has duplicate element"
        break

if not duplicate:
    print "No duplicate element"

Upvotes: 0

uselpa
uselpa

Reputation: 18917

Something like this?

def DupSearch(list):
    for i in range(len(list)):
        for j in range(i+1, len(list)):
            if list[i]==list[j]:
                print "Duplicate found"
                return
    print "No duplicated"

Upvotes: 1

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