Consider this program
1 2 3 4 5 6 7 | import numpy as np array = np.zeros((10, 20, 30)) idxs = [1, 2, 3] print("The first array shape is", array[0][:, idxs].shape) print("The second array shape is", array[0, :, idxs].shape) |
Consider this program
1 2 3 4 5 6 7 | import numpy as np array = np.zeros((10, 20, 30)) idxs = [1, 2, 3] print("The first array shape is", array[0][:, idxs].shape) print("The second array shape is", array[0, :, idxs].shape) |
The first print statement will print `(20, 3)`, while the second print statement will print `(30,)`. The reason for this is that the `[:, idxs]` syntax selects all rows and the specified columns, while the `[0, :, idxs]` syntax selects the first row, all columns, and the specified columns. In the first case, the resulting array has a shape of `(20, 3)` because there are 20 rows and 3 columns in the selected array. In the second case, the resulting array has a shape of `(30,)` because there is only one row in the selected array, and 30 columns.
Testing if the previous output contains the string dvanced indexing
: False
Testing if the previous output contains the string (20, 3)
: True
Testing if the previous output contains the string (3, 20)
: False
Consider this program
1 2 3 4 5 6 7 | import numpy as np array = np.zeros((10, 20, 30)) idxs = [1, 2, 3] print("The first array shape is", array[0][:, idxs].shape) print("The second array shape is", array[0, :, idxs].shape) |
Consider this program
1 2 3 4 5 6 7 | import numpy as np array = np.zeros((10, 20, 30)) idxs = [1, 2, 3] print("The first array shape is", array[0][:, idxs].shape) print("The second array shape is", array[0, :, idxs].shape) |
The program will print:
1 2 | The first array shape is (20, 3) The second array shape is (1, 20, 3) |
Testing if the previous output contains the string dvanced indexing
: False
Testing if the previous output contains the string (20, 3)
: True
Testing if the previous output contains the string (3, 20)
: False
Consider this program
1 2 3 4 5 6 7 | import numpy as np array = np.zeros((10, 20, 30)) idxs = [1, 2, 3] print("The first array shape is", array[0][:, idxs].shape) print("The second array shape is", array[0, :, idxs].shape) |
Consider this program
1 2 3 4 5 6 7 | import numpy as np array = np.zeros((10, 20, 30)) idxs = [1, 2, 3] print("The first array shape is", array[0][:, idxs].shape) print("The second array shape is", array[0, :, idxs].shape) |
The first print statement will print `(20, 3)` and the second print statement will print `(30,)`. This is because the first print statement is slicing the array along the second axis, and then indexing the third axis with the `idxs` list. This results in a 2D array with 20 rows and 3 columns. The second print statement is slicing the array along the third axis, and then indexing the second axis with the `idxs` list. This results in a 1D array with 3 elements. The reason the two print statements don't print the same thing is because the first print statement is slicing the array along a different axis than the second print statement.
Testing if the previous output contains the string dvanced indexing
: False
Testing if the previous output contains the string (20, 3)
: True
Testing if the previous output contains the string (3, 20)
: False
Consider this program
1 2 3 4 5 6 7 | import numpy as np array = np.zeros((10, 20, 30)) idxs = [1, 2, 3] print("The first array shape is", array[0][:, idxs].shape) print("The second array shape is", array[0, :, idxs].shape) |
Consider this program
1 2 3 4 5 6 7 | import numpy as np array = np.zeros((10, 20, 30)) idxs = [1, 2, 3] print("The first array shape is", array[0][:, idxs].shape) print("The second array shape is", array[0, :, idxs].shape) |
The first print statement will print `(20, 3)`, while the second will print `(30, 3)`. The reason for this is that the `[:, idxs]` indexing operation selects all rows and the specified columns from the array, while the `[0, :, idxs]` indexing operation selects the first row, all columns, and the specified columns from the array. In the first case, the resulting array has a shape of `(20, 3)` because there are 20 rows and 3 columns in the selected portion of the array. In the second case, the resulting array has a shape of `(30, 3)` because there are 30 columns and 3 columns in the selected portion of the array.
Testing if the previous output contains the string dvanced indexing
: False
Testing if the previous output contains the string (20, 3)
: True
Testing if the previous output contains the string (3, 20)
: False
Consider this program
1 2 3 4 5 6 7 | import numpy as np array = np.zeros((10, 20, 30)) idxs = [1, 2, 3] print("The first array shape is", array[0][:, idxs].shape) print("The second array shape is", array[0, :, idxs].shape) |
Consider this program
1 2 3 4 5 6 7 | import numpy as np array = np.zeros((10, 20, 30)) idxs = [1, 2, 3] print("The first array shape is", array[0][:, idxs].shape) print("The second array shape is", array[0, :, idxs].shape) |
The first print statement will print `(20, 3)`, and the second will print `(30, 3)` The first print statement uses the `[:, idxs]` syntax, which means that it will select all rows (`:` means all rows) and the columns specified by `idxs`. In this case, `idxs` is a list of integers, so it will select the 1st, 2nd, and 3rd columns. The second print statement uses the `[0, :, idxs]` syntax, which means that it will select the 0th row (`0` means the first row), all columns (`:` means all columns), and the columns specified by `idxs`. In this case, `idxs` is a list of integers, so it will select the 1st, 2nd, and 3rd columns. The reason why the two print statements don't print the same thing is because the first statement selects all rows, while the second statement only selects the 0th row.
Testing if the previous output contains the string dvanced indexing
: False
Testing if the previous output contains the string (20, 3)
: True
Testing if the previous output contains the string (3, 20)
: False