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Python practice problems help beginners to become experts in a python programming language with a small amount of practice effort.
Write a NumPy program to remove dimensions of size 1 from a shape.
shape (2, 1, 3)
(2, 1, 3) (2, 3)
np.squeeze.import numpy as npa = np.zeros((2, 1, 3))print(a.shape, np.squeeze(a).shape)(2, 1, 3) (2, 3)
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Write a NumPy program to find the ith element (counting row by row) of a 2-D array.
[[4, 8, 7], [2, 3, 6]], i = 5
3 (np.int64(1), np.int64(1))
flat[i - 1] for the 5th element, or np.unravel_index for its row and column.import numpy as npa = np.array([[4, 8, 7], [2, 3, 6]])i = 5print(a.flat[i - 1], np.unravel_index(i - 1, a.shape))3 (np.int64(1), np.int64(1))
The 5th element (index 4) is in row 1, column 1.
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Write a NumPy program to change the data type of an array.
[[4, 8, 7], [2, 3, 6]]
int32 float64 [[4. 8. 7.] [2. 3. 6.]]
astype() returns a converted copy.import numpy as npx = np.array([[4, 8, 7], [2, 3, 6]], dtype=np.int32)print(x.dtype)y = x.astype(np.float64)print(y.dtype)print(y)int32 float64 [[4. 8. 7.] [2. 3. 6.]]
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Write a NumPy program to find the index of the minimum value.
[76, 36, 56, 90]
1
argmin.import numpy as npprint(np.argmin([76, 36, 56, 90]))1
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Write a NumPy program to find the index of the maximum value.
[76, 36, 56, 90]
3
argmax.import numpy as npprint(np.argmax([76, 36, 56, 90]))3
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Write a NumPy program to find the union of two arrays.
[56, 18, 28, 36], [76, 36, 56]
[18 28 36 56 76]
np.union1d.import numpy as npprint(np.union1d([56, 18, 28, 36], [76, 36, 56]))[18 28 36 56 76]
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Write a NumPy program to find the unique values of array1 that are not in array2.
[56, 18, 28, 36], [76, 36, 56]
[18 28]
np.setdiff1d.import numpy as npprint(np.setdiff1d([56, 18, 28, 36], [76, 36, 56]))[18 28]
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Write a NumPy program to get the unique elements of an array.
[25, 33, 10, 45, 33, 10]
[10 25 33 45] [25 33 10 45]
np.unique returns them sorted; use the index to keep first-seen order.import numpy as npa = np.array([25, 33, 10, 45, 33, 10])print(np.unique(a))_, first = np.unique(a, return_index=True)print(a[np.sort(first)])[10 25 33 45] [25 33 10 45]
return_index gives each value’s first position; sorting those keeps the original order.
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Write a NumPy program to find the common elements of two arrays.
[56, 18, 28, 36], [76, 36, 56]
[36 56]
np.intersect1d (sorted result).import numpy as npprint(np.intersect1d([56, 18, 28, 36], [76, 36, 56]))[36 56]
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Write a NumPy program to find the real and imaginary parts of complex numbers.
[6+2j, 10+5j]
Real: [ 6. 10.] Imaginary: [2. 5.]
.real and .imag.import numpy as npa = np.array([6 + 2j, 10 + 5j])print("Real:", a.real, "Imaginary:", a.imag)Real: [ 6. 10.] Imaginary: [2. 5.]
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