4

Note: I found the answer and answered my own question, but I have to wait 2 days to accept my answer.

How do I initialize a numpy array of size 800 by 800 with other values besides zero? :

array = numpy.zeros((800, 800))

I am looking for a solution like this, where I could pass in a list (or lists) of values.

 array = numpy.array([[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
                        [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]])

Edit: I do not want to fill it with identical values.

I wanted a quick code example that demonstrates how this works without a long detailed example like I find in the other questions. I also want something simple to understand like converting a python array into a numpy array. I also am looking for the specific case of a 2D array.

Rock Lee
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    I'm not sure I got the question. Do you want to build an array filled with `1`s, or filled with any value you input? Also, why you wrote the code of an array 30x30 filled with 1? – rafaelc May 23 '15 at 22:15
  • I found the answer to my question. I think it is useful since I couldn't find such a simple answer anywhere on the other answers I checked. Also, I do not want to fill with identical values. I'd like to add my answer to help others. So I would like if it was not marked as duplicate. – Rock Lee May 23 '15 at 22:35
  • Have you read through the documentation? – wwii May 23 '15 at 22:48
  • @wwii No, it is so huge and vast, and hard to find a simple example anywhere. – Rock Lee May 23 '15 at 23:11
  • [http://docs.scipy.org/doc/numpy/reference/routines.array-creation.html#array-creation-routines](http://docs.scipy.org/doc/numpy/reference/routines.array-creation.html#array-creation-routines) – wwii May 23 '15 at 23:51

2 Answers2

7

You can use fill method to init the array.

x = np.empty(shape=(800,800))
x.fill(1)
Wang Hui
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2

Found out the answer myself: This code does what I want, and shows that I can put a python array ("a") and have it turn into a numpy array. For my code that draws it to a window, it drew it upside down, which is why I added the last line of code.

# generate grid
    a = [ ]
    allZeroes = []
    allOnes = []

    for i in range(0,800):
        allZeroes.append(0)
        allOnes.append(1)

    # append 400 rows of 800 zeroes per row.
    for i in range(0, 400):
        a.append(allZeroes)

    # append 400 rows of 800 ones per row.
    for i in range(0,400):
        a.append(allOnes)


#So this is a 2D 800 x 800 array of zeros on the top half, ones on the bottom half.
array = numpy.array(a)

# Need to flip the array so my other code that draws 
# this array will draw it right-side up
array = numpy.flipud(array)
Rock Lee
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