Selection from a list or dictionary

Operators and keywords for selecting from lists or dictionaries.

function semantics
except Exclude items of one list or dictionary from another
first First item of a list or first entry of a dictionary
Index, Index At Select items from a list or entries from a dictionary
inter Intersection of two lists or dictionaries
last Last item of a list or last entry of a dictionary
next Immediately following item/s
prev Immediately preceding item/s
sublist Sublist of a list
union Union of two lists or dictionaries
where Copies of indexes of a list, or keys or of a dictionary
xprev Nearby list items

q-SQL