python - How to print a 2D array in a "pretty" format? -

hello let's have 2d array a = [[1,2,1,2], [3,4,5,3], [8,9,4,3]] , print out in grid table. far code have is:

def printarray(a):     row in range(len(a[0])):         col in range (len(a[0])):             b = print("{:8.3f}".format(a[row][col]), end = " ")         print(b) 

when printed out gives me:

  1.000    2.000    1.000    2.000 none   3.000    4.000    5.000    3.000 none   8.000    9.000    4.000    3.000 none 

and error:

file "hw8pr2.py", line 17, in printarray b = print("{:8.3f}".format(a[row][col]), end = " ")  indexerror: list index out of range 

can tell me why happening? don't want 'none' @ end of each row either. want output:

  1.000    2.000    1.000    2.000   3.000    4.000    5.000    3.000   8.000    9.000    4.000    3.000 

there 3 main issues code have posted: way of iterating through array, assignment of b variable return of print statement, , printing of b variable.

firstly, way iterating through array counter-intuitive. can use

def printarray(arr):     row in arr:         item in row:             # code printing 

to make more clear.

secondly, understanding of print statement seems bit lacking. print statement takes in argument , prints out directly, there no need assign variable. since print statement has no official return, automatically returns none, ties in next point explain nones @ end of print statements.

finally, printing of b variable has value none assigned discussed above produces nones see.

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to fix code, use following solution.

a = [[1,2,1,2], [3,4,5,3], [8,9,4,3]]  def printarray(arr):     row in arr:         item in row:             print("{:8.3f}".format(item), end = " ")         print("")  printarray(a) 

other things stated above, code differs adding print(""), equivalent new line, after every row in array.