#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Numpy 2D array examples

Important: numpy offers many useful functions that operate on an entire array
           without using a for-loop (or any loop structure). Therefore, 
           please ** avoid using loops as far as possible! **
           However, if you do need to traverse through an array and "visit" 
           each element, you can use nested for-loops, as described in the 
           example below. 
           
           For Task-2 and Task-4, DO NOT use loop structures! 
           Please go through all the functions we discussed in the lectures.

           For Task-1 and Task-3, you CAN use loop structures. 

@author: Ashesh Mahidadia

"""

import numpy as np 

a1 = np.array([ [-24,  10, 2.5, 5.8], 
                [ 16,  -4,  18, 7.1],
                [ 3.8,  5, 5.9, 3.7]])

# Let's print each element value, along with row and column indices

(rows, cols) = a1.shape

for i in range(rows) :
    for j in range(cols) :
        print("Row index: ", i , ", Column index: ", j, ", Value is ", a1[i,j])
    

# Let's create a new 2D array with 4 rows and 6 columns, of type float64

a2 = np.zeros( (4, 6), dtype=np.float64)   
(rows, cols) = a2.shape

# Let's assign random numbers to each element
# The function np.random.random() returns floats in the half-open interval [0.0, 1.0).

for i in range(rows) :
    for j in range(cols) :
        a2[i,j] = np.random.random() * 100
        

max_val = np.max(a1)    
print  ( max_val )   

idx_max = np.argmax(a1)    
print  ( idx_max )  

(i, j) = np.unravel_index(9, (3,4))
print("i is " + str(i) + ", j is " + str(j) )



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