Python cannot input values into 2d array

Question

I want to input some values into a 2D array.

It works for the first part when I input into arr[days][count] , however, when I input it the second time when while is days>1 , it seems like it doesn't work.

For example, is days is 3 and numcows is 2, I can only input values into arr[1][1] not to arr[2][0] and onwards.

arr = [[0 for row in range(week+1)] for column in range(numcows)]

for days in range(1,week+1):
    count=0
    for count in range(numcows):
        while days == 1:
            arr[0][count] = float(input ("Enter cow ID"))
        ...
            arr[days][count] = daytotal
            count = count+1
            break
        while days>1:
            for count in range(numcows):
           ....
                arr[days][count] = daytotal #doesn't work 
                count = count+1
    days = days+1

What is wrong with my code?

Answer 1

I am not sure what you want to accomplish, bur looks like you want to create a 2D array, in which first row if cow ID and next n-1 rows are numbers of cows in n-1 weeks. If that is the case, the code written above seems incorrect.

• With a for loop you don't need a separate increment
• seems like you are using while loop for if, remember the variable used in while conditions must be manipulated within loop

I have written a code to add values to a 2X3 array with all user inputs and it works fine -

week=2
numcows=3
arr = [[0 for row in range(week+1)] for column in range(numcows)]

for days in range(1,week+1):
    for count in range(numcows):
        if days == 1:
            arr[0][count] = float(input ("Enter cow ID"))
            arr[days][count] = float(input ("Number of cows on Day " + str(days)))
        if days>1:
            arr[days][count] = float(input ("Number of cows on Day " + str(days)))