I’m trying to compare floating numbers that are stored in numpy arrays. I would like them to be compared with a tolerance and every number of the array should be compared with every number of the other array. My attempt is shown underneath, I used two simple arrays as examples but it has the problem that it only compares numbers with the same indices.
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b_y_ion_mass = np.array([1.000, 2.1300, 3.4320, 6.0000]) 2
observed_mass_array = np.array([0.7310, 2.2300, 5.999, 8.000, 9.000])3
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abs_tol = 0.2 5
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for (fragment, mass) in zip(b_y_ion_mass, observed_mass_array): 7
if (fragment+abs_tol)> mass and (fragment-abs_tol)< mass:8
print(mass)9
It would be great if anyone could help me.
Thank you.
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Answer
Use np.isclose with atol = abs_tol.
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import numpy as np2
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b_y_ion_mass = np.array([1.000, 2.1300, 3.4320, 6.0000]) 4
observed_mass_array = np.array([0.7310, 2.2300, 5.999, 8.000, 9.000])5
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abs_tol = 0.27
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np.isclose( b_y_ion_mass, observed_mass_array[ :, None ] , atol = abs_tol )9
# columns rows10
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# array([[False, False, False, False],12
# [False, True, False, False],13
# [False, False, False, True],14
# [False, False, False, False],15
# [False, False, False, False]])16
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# Compares18
# [1.000, 2.1300, 3.4320, 6.0000]19
# [0.7310, 20
# 2.2300, True21
# 5.999, True 22
# 8.000, 23
# 9.000]24
To get the observed masses:
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np.isclose( b_y_ion_mass, observed_mass_array[ :, None ], 2
atol = abs_tol ) * observed_mass_array[ :, None ]3
Result
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array([[0. , 0. , 0. , 0. ],2
[0. , 2.23 , 0. , 0. ],3
[0. , 0. , 0. , 5.999],4
[0. , 0. , 0. , 0. ],5
[0. , 0. , 0. , 0. ]])6