for loop and lists, new to python and programming [closed]

Question

list = [3,4,5,6]
a = 4
for x in list:
    if x <= 4:
        a += x
print (a)

#can someone explain what the steps and how I got answer 11 when I print a?

Answer 1

If you use VSCode or Pycharm you have Debug option to understand what is happening in each step. Let's debug it:

a = 4

• first loop:

  x = 3 and it's add to a variable that was 4, so a = 4 + 3 and now a = 7

• second loop:

  x = 4 and it's equal to 4, so it's add to a variable that was 7, so a = 7 + 4 and now a = 11

• third and fourth loop:

  x = 5 and x = 6 and they are smaller than 4, so nothing happen.

and finally a is 11

Answer 2

list = [3,4,5,6]
a = 4
for x in list:  

First iteration where x=3

if x<=4 === if 3<=4:  
condition True, if block is executed value a will   
a+=x ==== a=a+x
a=4+3 === a=7

Second iteration where x=4

if x<=4 === if 4<=4:  
condition True , if block is executed value a will  
a+=x ==== a=a+x
a=7+4 === a=11  

Third iteration where x=5

if x<=4 === if 5<=4:
condition False  

Fourth iteration where x=6

if x<=6 === if 6<=4:  
condition False  

No more values in list ,so for loop will terminate

print (a)  
O/P --- 11