to find the sum of only the negative numbers of the list-CodePudding

when i used for loop for length of the list I got the correct answer.But when I use for loop for I in range list: I got the correct wrong answer enter image description here the first Image shows when value of i is taken.the second image shoes when for loop is take for length of list.what's the problem here? enter image description here

CodePudding user response：

You can use the filter(to filter negative numbers) and then sum them -

>>> p = [1,2,-3,4,-4,5,6]
>>> sum(filter(lambda x: x < 0, p))
-7

CodePudding user response：

you are indexing the list like this p[1],p[2],p[-3]...

instead you should iterate through the values

p = [1,2,-3,4,-4,5,6]
t = 0
for i in p:
    if i < 0:
        t  = i
print(t)

or use range(len(p)):

p = [1,2,-3,4,-4,5,6]
t = 0
for i in range(len(p)):
    if p[i] < 0:
        t  = p[i]
print(t)

CodePudding user response：

This is the python code you had in the posted picture.

p = [1,2,-3,4,-4,5,6]
t = 0
for i in p:
   if p[i] < 0:
     t =p[i]
print(t)

when you use for i in p , we iterate through the list unlike accessing the list values by their index If you print each of the value during the loop

for i in p:
     print(i)
output: 
1
2
-3
4
-4
5
6

Also note that p[-3] indicates 3rd element from tail of the list so the values p[i] in your code are p[1],[2],p[-3],p[4],p[-4],p[5],p[6] equivalent to 2,-3,-4,-4,5,6 giving you a result of ((-3) (-4) (-4)) = -11