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other:python:misc_by_jyp [2022/02/21 14:47] jypeter [numpy related stuff] Added np.unique example |
other:python:misc_by_jyp [2022/02/21 15:15] jypeter [numpy related stuff] |
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>>> vals | >>> vals | ||
array([1. , 2. , 1. , 2. , 2. , 1.5, 1. , 1.5, 2. , 1.5]) | array([1. , 2. , 1. , 2. , 2. , 1.5, 1. , 1.5, 2. , 1.5]) | ||
+ | |||
>>> np.unique(vals) | >>> np.unique(vals) | ||
array([1. , 1.5, 2. ]) | array([1. , 1.5, 2. ]) | ||
- | >>> np.unique(vals, return_counts=True) | + | >>> unique_vals, nb_unique = np.unique(vals, return_counts=True) |
- | (array([1. , 1.5, 2. ]), array([3, 3, 4])) | + | >>> unique_vals |
- | >>> np.sort(vals) # Sorted copy, in order to check the result | + | array([1. , 1.5, 2. ]) |
+ | >>> nb_unique | ||
+ | array([3, 3, 4]) | ||
+ | |||
+ | >>> sorted_vals = np.sort(vals) # Sorted copy, in order to check the result | ||
+ | >>> sorted_vals | ||
array([1. , 1. , 1. , 1.5, 1.5, 1.5, 2. , 2. , 2. , 2. ])</code> | array([1. , 1. , 1. , 1.5, 1.5, 1.5, 2. , 2. , 2. , 2. ])</code> | ||
+ | === Applying a ufunc over all the elements of an array === | ||
+ | |||
+ | There are all sorts of //ufuncs// (Universal Functions), and we will just use below ''add'' from the [[https://numpy.org/doc/stable/reference/ufuncs.html#math-operations|math operations]], applied on the arrays defined in [[#finding_and_counting_unique_values|Finding and counting unique values]] | ||
+ | |||
+ | <code># Get the sum of all the elements of 'vals' | ||
+ | >>> np.add.reduce(vals) | ||
+ | 15.5 | ||
+ | >>> np.add.reduce(sorted_vals) | ||
+ | 15.5 | ||
+ | >>> vals.sum() # The usual and easy way to do it | ||
+ | 15.5</code> | ||
/* | /* |