Exercises

What is the command to import NumPy as np?
Create an array with \(10\) zeros.
Create an array with \(10\) ones.
Create an array with \(10\) fives.
Create a diagonal matrix with \(5\) threes down the diagonal.
Create an array of the integers from \(10\) to \(50\).
Create an array of the even integers from \(10\) to \(50\).
Create a \(3\times 3\) matrix with values ranging from \(0\) to \(8\).
Create the \(3\times 3\) identity matrix.
Use NumPy to generate a random number between \(0\) and \(1\).
Use NumPy to generate an array of \(25\) random numbers sampled from a standard normal distribution.

Create The following \(10\times 10\) matrix.

array([[ 0.01,  0.02,  0.03,  0.04,  0.05,  0.06,  0.07,  0.08,  0.09,  0.1 ],
       [ 0.11,  0.12,  0.13,  0.14,  0.15,  0.16,  0.17,  0.18,  0.19,  0.2 ],
       [ 0.21,  0.22,  0.23,  0.24,  0.25,  0.26,  0.27,  0.28,  0.29,  0.3 ],
       [ 0.31,  0.32,  0.33,  0.34,  0.35,  0.36,  0.37,  0.38,  0.39,  0.4 ],
       [ 0.41,  0.42,  0.43,  0.44,  0.45,  0.46,  0.47,  0.48,  0.49,  0.5 ],
       [ 0.51,  0.52,  0.53,  0.54,  0.55,  0.56,  0.57,  0.58,  0.59,  0.6 ],
       [ 0.61,  0.62,  0.63,  0.64,  0.65,  0.66,  0.67,  0.68,  0.69,  0.7 ],
       [ 0.71,  0.72,  0.73,  0.74,  0.75,  0.76,  0.77,  0.78,  0.79,  0.8 ],
       [ 0.81,  0.82,  0.83,  0.84,  0.85,  0.86,  0.87,  0.88,  0.89,  0.9 ],
       [ 0.91,  0.92,  0.93,  0.94,  0.95,  0.96,  0.97,  0.98,  0.99,  1.  ]])

Create an array of 20 linearly spaced points between 0 and 1.

Create a 2D array of numbers from 0 to 49 as follows:

arr_2d = np.arange(50).reshape(5,10)

Using array slicing write down the command that will produce the following outputs.

(a)

Output:
array([[12, 13, 14, 15],
        [22, 23, 24, 25],
        [32, 33, 34, 35]])

(b)

Output:
30

(c)

Output:
array([[ 2],
       [12],
       [22],
       [32],
       [42]])

Create the following matrix.
```
mat = np.arange(1,26).reshape(5,5)
mat
```
1. Find the sum of all values in mat.
2. Find the standard deviation of the values in mat.
3. Find the sum of all columns in mat.