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    Membership expressions
    
    

    
    

    
    

    
    
    
    

    



    

        Membership expressions

        Membership expressions are used to check that a value is a member of a collection value.

            An membership expression is a code fragment which produces a Boolean value, which can then be used as an input for other operations: print, write, method call and so forth.

            Membership expressions can have one of the following forms:

            

                a in b, where a is any value and b is a collection
                b contains a, where a is any value and b is a collection
                a contains any b, where a and b are collections
                a contains all b, where a and b are collections
            
            Or the negative forms:

            
            a not in b, where a is any value and b is a collection
            b not contains a, where a is any value and b is a collection
            a not contains any b, where a and b are collections
            a not contains all b, where a and b are collections
        
        
        
            Text membership
        
        Text membership expressions check whether a Character or Text value belongs to a given Text value.

            When checking for any or all, the collection of characters can be specified using a Text,
            which is then treated as collection of characters.
        

        
            
        
        
            Range membership
        
        Range membership expressions check whether a value belongs to a given Range value.

        

        
            
        

        
            List membership
        
        List membership expressions check whether a value belongs to a given List value.

        

        
            
        


        
            Set membership
        
        Set membership expressions check whether a value belongs to a given Set value.

        

        
            
        

        
            Tuple membership
        
        Tuple membership expressions check whether a value belongs to a given Tuple value.

        

        
            
        

        
            Dictionary membership
        
        Dictionary membership expressions check whether a Dictionary value contains a given Text key.

            They are equivalent to using Set membership expressions on dict.keys.

            To check for value membership, you should use membership expressions on dict.values.