packages/vaex-core/vaex/selections.py
def _depending_columns(self, ds):
        '''Find all columns that this selection depends on for df ds'''
        depending = set()
        for expression in self.expressions:
            expression = ds._expr(expression)  # make sure it is an expression
            depending |= expression.variables()
        if self.previous_selection:
            depending |= self.previous_selection._depending_columns(ds)
        return depending
def _depending_columns(self, ds):
        '''Find all columns that this selection depends on for df ds'''
        depending = set()
        for expression in self.expressions:
            expression = ds._expr(expression)  # make sure it is an expression
            depending |= expression.variables()
        if self.previous_selection:
            depending |= self.previous_selection._depending_columns(ds)
        return depending
Find all columns that this selection depends on for df ds