Course Content
Ultimate NumPy
Ultimate NumPy
Boolean Indexing in 2D Arrays
Boolean indexing in 2D and higher-dimensional arrays works similarly to 1D arrays. However, the boolean array must have the same number of dimensions as the initial array (e.g., 2D for two-dimensional arrays). The returned array, however, will be 1D.
import numpy as np array_2d = np.array([ [1, 2, 3], [4, 5, 6], [7, 8, 9] ]) # Retrieving elements less than 3 or greater than OR greater than or equal to 8 print(array_2d[(array_2d < 3) | (array_2d >= 8)])
The boolean array on the right is the resulting boolean array of these two combined conditions. Once again, purple elements match the conditions, and green elements don't. So when applying array_2d[(array_2d < 3) | (array_2d >= 8)], we get a 1D array of purple elements.
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You are analyzing the temperatures recorded in two different cities over four days. The temperatures are stored in the city_temperatures array, where each row represents a city and each column represents a day.
-
Use boolean indexing to include only the temperatures that are less than or equal to
15degrees OR greater than30degrees Celsius. -
Print the resulting array.
Switch to desktop for real-world practiceContinue from where you are using one of the options belowThanks for your feedback!
Boolean Indexing in 2D Arrays
Boolean indexing in 2D and higher-dimensional arrays works similarly to 1D arrays. However, the boolean array must have the same number of dimensions as the initial array (e.g., 2D for two-dimensional arrays). The returned array, however, will be 1D.
import numpy as np array_2d = np.array([ [1, 2, 3], [4, 5, 6], [7, 8, 9] ]) # Retrieving elements less than 3 or greater than OR greater than or equal to 8 print(array_2d[(array_2d < 3) | (array_2d >= 8)])
The boolean array on the right is the resulting boolean array of these two combined conditions. Once again, purple elements match the conditions, and green elements don't. So when applying array_2d[(array_2d < 3) | (array_2d >= 8)], we get a 1D array of purple elements.
Swipe to show code editor
You are analyzing the temperatures recorded in two different cities over four days. The temperatures are stored in the city_temperatures array, where each row represents a city and each column represents a day.
-
Use boolean indexing to include only the temperatures that are less than or equal to
15degrees OR greater than30degrees Celsius. -
Print the resulting array.
Switch to desktop for real-world practiceContinue from where you are using one of the options belowThanks for your feedback!
Switch to desktop for real-world practiceContinue from where you are using one of the options below