UnboundLocalError: local variable referenced before assignment #

February 5, 2022

Having issue with the code, I’m getting error with this code for using class and method. Please explain me the error I’m facing.

class Solution():
    def __init__(self,list1,list2):
        self.list1=list1
        self.list2=list2
    def medianOfList(self):
        self.list1=list1
        self.list2=list2
        list1=list1+list2
        l=len(list1)
        sum=0
        for i in range(l):
            sum+=list1[i]
        return sum/l
list1=[1,2]
list2=[3,100]
m=Solution(list1,list2)
m.medianOfList()

UnboundLocalError                         Traceback (most recent call last)
Input In [18], in <module>
     19 list2=[3,100]
     20 m=Solution(list1,list2)
---> 21 m.medianOfList()

Input In [18], in Solution.medianOfList(self)
      9 def medianOfList(self):
---> 10     self.list1=list1
     11     self.list2=list2
     12     list1=list1+list2

UnboundLocalError: local variable 'list1' referenced before assignment

>Solution :

Your error: UnboundLocalError: local variable 'list1' referenced before assignment was coming because you have not defined list1 in medianOfList(self) but you are trying to access it.

Here’s my solution:

class Solution():
    def __init__(self,list1,list2):
        self.list1=list1
        self.list2=list2
    def medianOfList(self,list1,list2):
        self.list1=list1
        self.list2=list2
        list1=list1+list2
        l=len(list1)
        sum=0
        for i in range(l):
            sum+=list1[i]
        return sum/l
        
list1=[1,2]
list2=[3,100]
m=Solution(list1,list2)
m.medianOfList(list1,list2)