numpy.trim_zeros() in Python
Last Updated :
21 Jun, 2025
numpy.trim_zeros() removes the leading and trailing zeros from a 1-D array. It is often used to clean up data by trimming unnecessary zeros from the beginning or end of the array. Example:
Python
import numpy as np
a = np.array([0, 0, 3, 4, 0, 5, 0, 0])
res = np.trim_zeros(a)
print(res)
Explanation: np.trim_zeros(a) removes both leading and trailing zeros by default (trim='fb'). Zeros in the middle remain unchanged.
Syntax
numpy.trim_zeros(filt, trim='fb')
Parameter:
- filt (array_like): A 1-D array of numeric values from which zeros will be trimmed.
- trim (str, optional): Indicates which zeros to remove, 'f' for leading (front), 'b' for trailing (back) and 'fb' (default) for both.
Returns: A new 1-D NumPy array with the specified zeros removed.
Examples
Example 1: In this example, we use the parameter trim='f' to remove the leading zeros from the beginning of the array, while keeping the zeros at the end unchanged.
Python
import numpy as np
a = np.array([0, 0, 1, 2, 3, 0])
res = np.trim_zeros(a, trim='f')
print(res)
Explanation: np.trim_zeros(a, trim='f') removes only the leading zeros from the beginning of the array. Trailing zeros are preserved, resulting in [1, 2, 3, 0].
Example 2: In this example, we use the parameter trim='b' to remove the trailing zeros from the end of the array, while keeping the leading zeros at the beginning unchanged.
Python
import numpy as np
a = np.array([0, 1, 2, 0, 0])
res = np.trim_zeros(a, trim='b')
print(res)
Explanation: np.trim_zeros(a, trim='b') removes only the trailing zeros from the end of the array. Leading zeros are kept intact, resulting in [0, 1, 2].
Example 3: In this example, all elements are zeros. Since np.trim_zeros() removes zeros from both ends by default, the result is an empty array.
Python
import numpy as np
a = np.array([0, 0, 0, 0])
res = np.trim_zeros(a)
print(res)
Explanation: np.trim_zeros(a) removes zeros from both ends by default (trim='fb'). Since the array contains only zeros, the result is an empty array.
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