Python for Basic Data Analysis: NP.14 NumPy Exercises

Replace all odd numbers in the given array with -1

Start with:

exercise_1 = np.array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])

Desired output:

[ 0, -1, 2, -1, 4, -1, 6, -1, 8, -1]

Convert a 1-D array into a 2-D array with 3 rows

Start with:

exercise_2 = np.array([0, 1, 2, 3, 4, 5, 6, 7, 8])

Desired output:

[[ 0, 1, 2]
[3, 4, 5]
[6, 7, 8]]

Add 202 to all the values in given array

Start with:

exercise_3 = np.arange(4).reshape(2,-1)

Desired output:

[[202, 203]
[204, 205]]

Generate a 1-D array of 10 random integers. Each integer should be a number between 30 and 40 (inclusive)

Sample of desired output: 

[36, 30, 36, 38, 31, 35, 36, 30, 32, 34]

Your answer may contain different values but should fulfill the question requirements.

Find the positions of:

• elements in x where its value is more than its corresponding element in y, and
• elements in x where its value is equals to its corresponding element in y.

Start with these:

x = np.array([21, 64, 86, 22, 74, 55, 81, 79, 90, 89]) 
y = np.array([21, 7, 3, 45, 10, 29, 55, 4, 37, 18])

Desired output:

(array([1, 2, 4, 5, 6, 7, 8, 9]),) and (array([0]),)

Extract the first four columns of this 2-D array

Start with this: 

exercise_6 = np.arange(100).reshape(5,-1)

Desired output:

[[ 0 1 2 3]
[20 21 22 23]
[40 41 42 43]
[60 61 62 63]
[80 81 82 83]]