Python Numpy Problems

Python Numpy Practice Problems

Even integers from 1 to 20

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Python Practice › NumPy Programs › Program 16

Even integers from 1 to 20

EasyNumPy Programs · 16 of 100

Write a NumPy program to create an array of even integers from 1 to 20.

Output
[ 2  4  6  8 10 12 14 16 18 20]

Approach

  1. np.arange(2, 21, 2).

Solution

Python
import numpy as npprint(np.arange(2, 21, 2))
Output
[ 2  4  6  8 10 12 14 16 18 20]

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Integers from 1 to 20

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Python Practice › NumPy Programs › Program 15

Integers from 1 to 20

EasyNumPy Programs · 15 of 100

Write a NumPy program to create an array of integers from 1 to 20.

Output
[ 1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20]

Approach

  1. np.arange(1, 21).

Solution

Python
import numpy as npprint(np.arange(1, 21))
Output
[ 1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20]

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#16EasyEven integers from 1 to 20#17EasyOdd integers from 1 to 20#18EasyIntegers 1 to 100 in steps of 6#19Easy3 × 3 matrix

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Array of three ones

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Python Practice › NumPy Programs › Program 14

Array of three ones

EasyNumPy Programs · 14 of 100

Write a NumPy program to create an array of 3 ones.

Output
[1 1 1] [1. 1. 1.]

Approach

  1. np.ones(3, dtype=int).

Solution

Python
import numpy as npprint(np.ones(3, dtype=int), np.ones(3))
Output
[1 1 1] [1. 1. 1.]

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#15EasyIntegers from 1 to 20#16EasyEven integers from 1 to 20#17EasyOdd integers from 1 to 20#18EasyIntegers 1 to 100 in steps of 6

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Memory used by an array

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Python Practice › NumPy Programs › Program 13

Memory used by an array

EasyNumPy Programs · 13 of 100

Write a NumPy program to find the memory occupied by an array.

Output
5 8 40

Approach

  1. nbytes = number of items × bytes per item.

Solution

Python
import numpy as nparr = np.array([10, 34, 86, 26, 56], dtype=np.int64)print(arr.size, arr.itemsize, arr.nbytes)
Output
5 8 40

Line by line

Line 2

The dtype is fixed to int64 so the size is the same on every platform.

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More numpy programs

#14EasyArray of three ones#15EasyIntegers from 1 to 20#16EasyEven integers from 1 to 20#17EasyOdd integers from 1 to 20

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Create an array from values

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Python Practice › NumPy Programs › Program 12

Create an array from values

EasyNumPy Programs · 12 of 100

Write a NumPy program to create an array with the values 10, 34, 86, 26, 56.

Output
[10 34 86 26 56] int64

Approach

  1. np.array(list).

Solution

Python
import numpy as nparr = np.array([10, 34, 86, 26, 56])print(arr, arr.dtype)
Output
[10 34 86 26 56] int64

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#13EasyMemory used by an array#14EasyArray of three ones#15EasyIntegers from 1 to 20#16EasyEven integers from 1 to 20

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Element-wise less than

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Python Practice › NumPy Programs › Program 11

Element-wise less than

EasyNumPy Programs · 11 of 100

Write a NumPy program for an element-wise “less than” comparison.

Input
[6, 4], [2, 9]
Output
[False  True]

Approach

  1. np.less.

Solution

Python
import numpy as npprint(np.less([6, 4], [2, 9]))
Output
[False  True]

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#12EasyCreate an array from values#13EasyMemory used by an array#14EasyArray of three ones#15EasyIntegers from 1 to 20

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Element-wise greater or equal

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Python Practice › NumPy Programs › Program 10

Element-wise greater or equal

EasyNumPy Programs · 10 of 100

Write a NumPy program for an element-wise “greater or equal” comparison.

Input
[6, 4], [6, 3]
Output
[ True  True]

Approach

  1. np.greater_equal.

Solution

Python
import numpy as npprint(np.greater_equal([6, 4], [6, 3]))
Output
[ True  True]

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Element-wise greater than

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Python Practice › NumPy Programs › Program 9

Element-wise greater than

EasyNumPy Programs · 9 of 100

Write a NumPy program for an element-wise “greater than” comparison.

Input
[8, 3], [9, 1]
Output
[False  True]

Approach

  1. np.greater(a, b) or a > b.

Solution

Python
import numpy as npprint(np.greater([8, 3], [9, 1]))
Output
[False  True]

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#10EasyElement-wise greater or equal#11EasyElement-wise less than#12EasyCreate an array from values#13EasyMemory used by an array

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Are two arrays element-wise equal?

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Python Practice › NumPy Programs › Program 8

Are two arrays element-wise equal?

EasyNumPy Programs · 8 of 100

Write a NumPy program to test whether two arrays are element-wise equal.

Input
[3, 8, 5], [3, 8, 5]
Output
[ True  True  True] True

Approach

  1. == compares element by element; np.array_equal gives one answer.

Solution

Python
import numpy as npa, b = np.array([3, 8, 5]), np.array([3, 8, 5])print(a == b, np.array_equal(a, b))
Output
[ True  True  True] True

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Is a value a scalar?

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Python Practice › NumPy Programs › Program 7

Is a value a scalar?

EasyNumPy Programs · 7 of 100

Write a NumPy program to test whether a value is a scalar.

Input
8.9, [8.9]
Output
True False

Approach

  1. np.isscalar().

Solution

Python
import numpy as npprint(np.isscalar(8.9), np.isscalar([8.9]))
Output
True False

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#8EasyAre two arrays element-wise equal?#9EasyElement-wise greater than#10EasyElement-wise greater or equal#11EasyElement-wise less than

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