Question

HI I would like to ask how to write the function when my list is [[1,2,4],[0,3,2]]. Like merging them. I managed to do it separately only. The mean for [1,2,4] is 2.33 and so xbar return me [-1.33,-0.33,1.67] (is like [1,2,4] minus the 2.33. I need help for more lists. Thanks

>>> def mean(Ist): return sum(Ist)/len(Ist) >>> def xbar(data): i = 0 a = mean(data) for i in range(len(data)): data[i] -= a i += 1 return data >>> xbar([1,2,4]) [-1.3333333333333335, -0.3333333333333335, 1.6666666666666665] >>> >>> xbar([0,3,2]) [-1.6666666666666667, 1.3333333333333333, 0.33333333333333326] >>> >>> data = [[1,2,4),(0,3,2]] >>> xbar(data) Traceback (most recent call last): File "<pyshell#9>", line 1, in <module> xbar(data) File "<pyshell#3>", line 3, in xbar a = mean(data) File "<pyshell#1>", line 2, in mean return sum(Ist)/len(Ist) TypeError: unsupported operand type(s) for +: 'int' and 'list' >>>|

Answer 1

Answer

Here is your answer, Here we can use exception handling properties of pythhon. When we passed through the single list of element, we can easly perform sum() operation. But when we are passing a array of list(2_D array) , we can't perform sum() operation it will produce the above error. So we can handle this problem using exception handling. If there is exception occured during the runtime, we can convert the array of list into a single list, and can find the sum() of elements and length.

So here is your code for fixed code.

def mean(lst):
    return sum(lst)/len(lst)
def xbar(data):
    """
    Just modified with exception handling,If exception occurred, we will convert the array into list.
    """
    try:
        i=0
        a=mean(data)
        for i in range(len(data)):
            data[i]-=a
            i+=1
        return data
    except:
        #create a new list 
        new_data=[]
        #iterate through elements in the array of list, and create a new list with all elements in the array of list
        for row in data:
                a=mean(row)
                for i in row:
                    new_data.append(i-a)
        return new_data
data1=[[1,2,4],[0,3,2]]
data2=[0,3,2]
print(xbar(data1))

output

print(xbar(datai)) [-1.3333333333333335, -0.3333333333333335, 1.6666666666666665, -1.6666666666666667, 1.3333333333333333, 0.33333333333333 326]

Any doubt please comment, i am here to help you

Thanks in advance