Python programming with NumPy

get_ipython().system('pip install numpy')


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get_ipython().system('pip install --upgrade pip')


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get_ipython().system('pip install numpy --upgrade')


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# What is NumPy?
# Numpy is a numerical computing package!
# Pyhton cannot support the functionality what numpy provides directly
# Basic building block of Numpy is a powerful n dimentional array


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import numpy as np

array_one = np.array([1,2,3,4])

array_one


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number = [22,33,44,55,66]

array_two = np.array(number)

array_two


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# array of zeros

array_zeros = np.zeros((4,5))

array_zeros


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# Source: https://www.machinelearningplus.com/python/101-numpy-exercises-python/
# Q. Import numpy as `np` and print the version number.


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import numpy as np

get_ipython().system('pip install numpy')


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#or
import numpy as np

print(np.__version__)


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# Q. Create a 1D array of numbers from 0 to 9


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array_oneDim = np.array(range(0,10))

array_oneDim


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#Or

arr = np.arange(10) # arange is "array range"
arr


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# Q. Create a 3×3 numpy array of all True’s


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array_bool = np.ones((3,3), dtype = bool) # np.ones --> Return an array of ones with shape and type of input.
array_bool


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np.ones(5)


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np.ones(1)


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np.ones((5,1), dtype = int) # 5x1 matrix - rows x columns


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np.ones((5,), dtype = int)


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np.ones((2,1))


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s = (2,2)
np.ones(s)


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np.ones((5,), dtype = float)


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np.ones((5,), dtype = str)


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# Q. Extract all odd numbers from arr


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arr = np.array([0,1,2,3,4,5,6,7,8,9])
arr


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arr[arr % 2 == 1]


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# Q. Replace all odd numbers in arr with -1 without changing arr


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arr = np.arange(10)
out = np.where(arr % 2 ==1, -1, arr)
print(arr)
out