CODEWITHSUNDEEP
python-3.xlist
PN07815
PN07815

Reputation: 123

updating list in python3

I have this code snippet : I was expecting the output to be [1,1] when I print the list but I'm getting [0,0]. Since I have already initialised a and b as list variables , I thought the value of "result" would be updated to the values of a and b after the loop. My program is working fine if I return the values a and b but I was just wondering why the "result" isn't getting updated. I'm still learning Python so would appreciate any help 

a=0
b=0
arrayA=[7,9,1]
arrayB=[2,9,5]
result=[a,b]

for i in range(0,len(arrayA)): 
    if(arrayA[i]>arrayB[i]):
        a+=1           
    elif (arrayA[i]==arrayB[i]):
        continue            
    else:
        b+=1
print(result)

Blockquote

Thank you!

Upvotes: 0

Views: 36

Answers (2)

shahaf
shahaf

Reputation: 4973

complected objects like list (and more) get passed by reference, so this will get you the answer you want 

a=[0]
b=[0]
arrayA=[7,9,1]
arrayB=[2,9,5]
result=[a,b]

for i in range(0,len(arrayA)): 
    if(arrayA[i]>arrayB[i]):
        a[0]+=1           
    elif (arrayA[i]==arrayB[i]):
        continue            
    else:
        b[0]+=1
print(result)

Upvotes: 1

Eric Yang
Eric Yang

Reputation: 2750

result = [a,b], the variables a and b are not references. 

a=0
b=0
arrayA=[7,9,1]
arrayB=[2,9,5]


for i in range(0,len(arrayA)): 
    if(arrayA[i]>arrayB[i]):
        a+=1           
    elif (arrayA[i]==arrayB[i]):
        continue            
    else:
        b+=1

result=[a,b]
print(result)

Would be what you want

Upvotes: 1

Related Questions