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Conjunction, Disjunction and Negation. Boolean operators consider all null values to be false and all non null values to be true. The vectors created by boolean operators are binary vectors (containing only 1 where result is true, 0 where it is false). For example :
a = |1,2,3,0|
b = |0,5,6,7|
c = a and b
creates a vector c with values of 1 where the corresponding values of vector a and vector b are both non zero, and 0 otherwise. A missing value in either input vector will result in a missing value in the corresponding place in the output vector.
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