Polygon perimeter calculator

[EliKanevski]

For some reason when i assign a list to x this works perfectly fine, but when i take a list input i get an error. Does anyone know why?
Thank you.

print('*** QUESTION 4 ***')
def perimeter(points):
    d = 0
    len_points = len(points)
    if len(points) < 3:
        return 0
    for i in range(len_points):
        d += math.sqrt((points[i-1][0] - points[i][0])**2 + ((points[i-1][1] - points[i][1])**2))
    return d
x = list(input('please enter a list'))
print(type(x))
print(perimeter(x))```                                                                                                                                                              

[JayeshGChandan]

This will create a list of strings. I think you have to map it with the type.
e.g., x = list(map(type, input.split()))

In python 3 when we take input it's type is string so firstly you have to typecast it into integer.
x= list(map(int,input().split("")))
something like this..

[EliKanevski]

@shashwat-code I tried what you said, i first got an empty separator error, so i put an blank space there, then got an "invalid literal for int() with base 10: 'input...' " error message.
I tried give the input in a list and in just parentheses. (0,4),(3,3),(4,0),....
Also tried the same just with opening and closing square brackets, and got the same result.
Do you think it would work if I make an empty list in my function, and then append or concatanate the input to the list?
Thanks a lot. I appreciate your help!

[EliKanevski]

@JayeshGChandan I tried your code, it just returns the type to x and it remains a string.
Thank you for your help!

[JayeshGChandan]

My pleasure :)

…

On Mon, Dec 7, 2020, 22:24 EliKanevski ***@***.***> wrote: @JayeshGChandan <https://github.com/JayeshGChandan> I tried your code, it just returns the type to x and it remains a string. Thank you for your help! — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#4013 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AQPKJ5SUKOWOLJIUSAI73DTSTUCCPANCNFSM4UP2X3CA> .

Ok so you want to take input something like this:
[[2,3],[4,5],[6,7]]
Code
x= list(map(int,input().split(" ")))
y=[]
for i in range(0,len(x),2):
y.append([x[i],x[i+1]])
print(y)

Input:
1 2 3 4 5 6 7 8 9 0

Output
[ [1, 2 ], [3, 4 ], [5, 6 ], [7, 8 ], [ 9, 0 ] ]

I think so that works for you

[vitor592]

Galera sou novo por aqui estou entrando nesse mundo agora começando a estudar em Python !

Guys the final input code for you is:

while True:
    r = False
    x = input("please enter a list:").split(" ")
    for item in x:
        if not item.isnumeric():
            print("please enter a valid list separated by ' '")
            r = True
    if r:
        continue
    x = map(int, x)
    if len(x) % 2 != 0:
        print("the amount of provided numbers are odd and this cannot form pairs")
        continue
    y = x
    x = []
    for p1, p2 in zip(y[0:len(y)//2], y[len(y)//2:len(y)]):
        x.append([p1, p2])
    break

Input
1 2 3 4 5 6

Returned value
[[1, 2], [3, 4], [5, 6]]

The above code is resistant to all faulty input or errors, remember you can still use x variable as input to function and this is only input system and not the whole code of yours so only put this in place of input statement
😄

Final code

print('*** QUESTION 4 ***')
def perimeter(points):
    d = 0
    len_points = len(points)
    if len(points) < 3:
        return 0
    for i in range(len_points):
        d += math.sqrt((points[i-1][0] - points[i][0])**2 + ((points[i-1][1] - points[i][1])**2))
    return d
while True:
    r = False
    x = input("please enter a list:").split(" ")
    for item in x:
        if not item.isnumeric():
            print("please enter a valid list separated by ' '")
            r = True
    if r:
        continue
    x = map(int, x)
    if len(x) % 2 != 0:
        print("the amount of provided numbers are odd and this cannot form pairs")
        continue
    y = x
    x = []
    for p1, p2 in zip(y[0:len(y)//2], y[len(y)//2:len(y)]):
        x.append([p1, p2])
    break
print(perimeter(x))

[EliKanevski]

Thank you very much everyone for the help! Much appreciated!