Iterate over array and make calculation on elements

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I have an array that I want to sum specific elements while iterating through it. I struggle to find a way to do this with loop. The array shape is (25,25)

array 
  [ 92843,  86851,  91950,  98232,  83329,  94591,  88962,  97020,
        107113,  98452, 103242, 106442, 123032, 119063, 112971, 114715,
        108654, 114856, 109872, 124583, 120518, 112815, 120780, 127831,
        147174],
       [132633, 124073, 131357, 140331, 119041, 135131, 127089, 138601,
        153019, 140647, 147489, 152061, 175761, 170090, 161388, 163879,
        155221, 164080, 156960, 177976, 172169, 161165, 172544, 182617,
        210249],
       [159159, 148887, 157629, 168397, 142849, 162157, 152507, 166321,
        183623, 168776, 176986, 182473, 210913, 204108, 193665, 196655,
        186265, 196896, 188352, 213571, 206602, 193398, 207052, 219140,
        252298]

I want to print out results like below for each iteration

print(array[23][0]+array[23][1]) # 159159 + 148887 = 308046
print(array[22][0]+array[22][1]+array[22][2]) #132633 + 124073 + 131357 = 388063
print(array[21][0]+array[21][1]+array[21][2]+array[21][3]) # 92843 +  86851 + 91950 + 98232 = 369876 

Presenting each element as array[i][j], as you can see in each iteration i - 1, and the "length" of j increased one. Is there anyway I can use loop to do this task ? Thanks!

Try this:

for i, sub in enumerate(reversed(array)):
    print(sum(sub[:i]))

For example, if

array = [[ 1,  2,  3,  4,  5],
         [ 6,  7,  8,  9, 10],
         [11, 12, 13, 14, 15],
         [16, 17, 18, 19, 20],
         [21, 22, 23, 24, 25]]

the output would be

0    # last row, no elements summed
16   # 16 = 16
23   # 11 + 12 = 23
21   # 6 + 7 + 8 = 21
10   # 1 + 2 + 3 + 4 = 10

Looping over arrays and objects in JavaScript - Chingu, How do I iterate an array of objects in Node JS? There may be many ways of iterating over an array in Java, below are some simple ways. This is the simplest of all where we just have to use a for loop where a counter variable accesses each element one by one. For each loop optimizes the code, save typing and time. This article is contributed by Nikita Tiwari.

You may simply want the np.tril, followed by a np.sum(_, axis=0). This will give the sum of each row of the lower triangle of the matrix. Easily altered to give the upper triangle, if that's what you need.

print(np.sum(np.tril(array), axis=0))

NumPy Array Iterating, Iterate Through an Array with a For Loop Hints Hint 1 Remember the structure of a for for-in loop and it seems that is better method to iterate through arrays and objects. A bit late to the game but it's better to take arr.length out of the loop so for After the code has calculated the total for this loop, it refers back to the i++  NumPy package contains an iterator object numpy.nditer. It is an efficient multidimensional iterator object using which it is possible to iterate over an array. Each element of an array is visited using Python’s standard Iterator interface. Let us create a 3X4 array using arange () function and iterate over it using nditer.

In [661]: arr = np.arange(1,17).reshape(4,4)
In [662]: arr
Out[662]: 
array([[ 1,  2,  3,  4],
       [ 5,  6,  7,  8],
       [ 9, 10, 11, 12],
       [13, 14, 15, 16]])

In [666]: for i in range(3,-1,-1):
     ...:     c = arr[i,:4-i]
     ...:     print(c.sum(), c)
     ...:     
13 [13]
19 [ 9 10]
18 [5 6 7]
10 [1 2 3 4]

Node.js, To do that, we can use a loop to iterate over each element, repeating the to make sure that the counter variable i is less than the length of the steps array. Using the iterator variable as the index number is the fastest way to iterate the elements of an array: Dim items As Variantitems = Array(0, 1, 2, 3)Dim index As IntegerFor index = LBound(items) To UBound(items) 'assumes value can be implicitly converted to a String: Debug.Print items(index) Next.

freeCodeCamp Challenge Guide: Iterate Through an Array with a , Iterating over arrays and objects in JavaScript Transformation methods take an input array and produce an output array, while the callback  The returned list is not an array, but rather a NodeList object containing a collection of nodes: // select all anchor tags const anchors = document.querySelectorAll('a.open-article'); // TODO: iterate over `NodeList` elements and attach a click handler There are many ways to loop through a NodeList object in JavaScript. Let us look at them.

Iteration over lists | AP CSP (article), to do element-wise array calculations. Method 2 uses array syntax, where looping over array elements happens implicitly (this syntax is also found in Fortran  As you would in any other programming language, simply nest two for loops to iterate over the 2D array by index. If there's going to be a variable number of rows/columns, you can parse the return values of the GetArrayBounds() function to set the bounds of your iterations.

Iterating over arrays and objects in JavaScript, Loops offer a quick and easy way to do something repeatedly. The following example iterates through the elements in an array until it finds  In the code block, you can use the identifier. Each time R loops through the code, R assigns the next value in the vector with values to the identifier. Calculate values in a for loop. Let’s take another look at the priceCalculator() function. Earlier, we show you a few possibilities to adapt this function so you can apply a different VAT

Comments
  • The 3rd and the 2nd shared the same i. Do you mean 23,22,21? And why do you have difficulty looping through the index?
  • @knh190 yes you are right, I've edited the question
  • If you are using numpy state so. array is vague. Also try use the arr[23,0] style of indexing.
  • Thank you, but I received an error on the second line TypeError: 'numpy.int64' object is not callable
  • @Osca I can't reproduce that. Are you sure you typed in the code correctly?
  • Yes, I copy paste the code. Even for the example array you made, I received the same error. Im using python3
  • Thank you, but I want to print each layer's sum of the triangle, not just the sum of whole upper triangle
  • axis should be outside of np.tril.
  • @Osca that is what this returns. I have edited to make that more clear.