Orddict1 = Orddict2 = orddict(Key, Value)

Appends a new Value to the current list of values associated with Key.

An exception is generated if the initial value associated with Key is not a list of values.

Examples

1> OrdDict1 = orddict:from_list([{x, []}]).
[{x,[]}]
2> OrdDict2 = orddict:append(x, 1, OrdDict1).
[{x,[1]}]
3> OrdDict3 = orddict:append(x, 2, OrdDict2).
[{x,[1,2]}]
4> orddict:append(y, 3, OrdDict3).
[{x,[1,2]},{y,[3]}]

1> OrdDict1 = orddict:from_list([{a, no_list}]).
[{a,no_list}]
2> orddict:append(a, 1, OrdDict1).
** exception error: bad argument
     in operator  ++/2
        called as no_list ++ [1]
     in call from orddict:append/3

Orddict1 = Orddict2 = orddict(Key, Value)

Appends a list of values ValList to the current list of values associated with Key.

An exception is generated if the initial value associated with Key is not a list of values.

Examples

1> OrdDict1 = orddict:from_list([{x, []}]).
[{x,[]}]
2> OrdDict2 = orddict:append_list(x, [1,2], OrdDict1).
[{x,[1,2]}]
3> OrdDict3 = orddict:append_list(y, [3,4], OrdDict2).
[{x,[1,2]},{y,[3,4]}]

Orddict1 = Orddict2 = orddict(Key, Value)

Removes the item with key Key from dictionary OrdDict1.

Examples

1> OrdDict1 = orddict:from_list([{a, 1}, {b, 2}]).
[{a,1},{b,2}]
2> orddict:erase(a, OrdDict1).
[{b,2}]
3> orddict:erase(z, OrdDict1).
[{a,1},{b,2}]

Returns the value associated with Key in dictionary Orddict.

This function assumes that the Key is present in the dictionary. An exception is generated if Key is not in the dictionary.

Examples

1> OrdDict1 = orddict:from_list([{a, 1}, {b, 2}]).
[{a,1},{b,2}]
2> orddict:fetch(a, OrdDict1).
1
3> orddict:fetch(missing, OrdDict1).
** exception error: no function clause matching orddict:fetch(missing,[])

Keys = [Key]

Returns a list of all keys in a dictionary.

Examples

1> OrdDict1 = orddict:from_list([{a, 1}, {b, 2}]).
[{a,1},{b,2}]
2> orddict:fetch_keys(OrdDict1).
[a,b]

Pred = fun((Key, Value) -> boolean())

Orddict1 = Orddict2 = orddict(Key, Value)

Orddict2 is a dictionary of all keys and values in Orddict1 for which Pred(Key, Value) is true.

Examples

1> OrdDict1 = orddict:from_list([{a, 1}, {b, 2}]).
[{a,1},{b,2}]
2> orddict:filter(fun (K, V) -> V > 1 end, OrdDict1).
[{b,2}]

Searches for a key in a dictionary.

Returns {ok, Value}, where Value is the value associated with Key, or error if the key is not present in the dictionary.

Examples

1> OrdDict1 = orddict:from_list([{a, 1}, {b, 2}]).
[{a,1},{b,2}]
2> orddict:find(a, OrdDict1).
{ok,1}
3> orddict:find(c, OrdDict1).
error

Fun = fun((Key, Value, AccIn) -> AccOut)

Acc0 = Acc1 = AccIn = AccOut = Acc

Orddict = orddict(Key, Value)

Calls Fun on successive keys and values of Orddict together with an extra argument Acc (short for accumulator).

Fun must return a new accumulator that is passed to the next call. Acc0 is returned if the list is empty.

Examples

1> OrdDict1 = orddict:from_list([{a, 1}, {b, 2}]).
[{a,1},{b,2}]
2> orddict:fold(fun (K, V, Acc) -> [{K, V+100} | Acc] end, [], OrdDict1).
[{b,102},{a,101}]

Orddict = orddict(Key, Value)

Converts the Key-Value list List to a dictionary.

Examples

1> OrdDict = orddict:from_list([{2,b},{1,a},{3,c}]).
[{1,a},{2,b},{3,c}]

Returns true if Orddict has no elements; otherwise, returns false.

Examples

1> orddict:is_empty(orddict:new()).
true
2> orddict:is_empty(orddict:from_list([{a,1}])).
false

Returns true if Key is contained in dictionary Orddict; otherwise, returns false.

Examples

1> OrdDict = orddict:from_list([{1,a},{2,b},{3,c}]).
[{1,a},{2,b},{3,c}]
2> orddict:is_key(2, OrdDict).
true
3> orddict:is_key(aa, OrdDict).
false

Fun = fun((Key, Value1) -> Value2)

Orddict1 = orddict(Key, Value1)

Orddict2 = orddict(Key, Value2)

Calls Fun on successive keys and values of Orddict1 to return a new value for each key.

Examples

1> OrdDict1 = orddict:from_list([{a, 1}, {b, 2}]).
[{a,1},{b,2}]
2> orddict:map(fun (_K, V) -> V + 100 end, OrdDict1).
[{a,101},{b,102}]

Fun = fun((Key, Value1, Value2) -> Value)

Orddict1 = orddict(Key, Value1)

Orddict2 = orddict(Key, Value2)

Orddict3 = orddict(Key, Value)

Merges two dictionaries, Orddict1 and Orddict2, to create a new dictionary.

All the Key-Value pairs from both dictionaries are included in the new dictionary.

If a key occurs in both dictionaries, Fun is called with the key and both values to return a new value.

merge/3 can be defined as follows, but is faster:

merge(Fun, D1, D2) ->
    fold(fun (K, V1, D) ->
                 update(K, fun (V2) -> Fun(K, V1, V2) end, V1, D)
         end, D2, D1).

Examples

1> OrdDict1 = orddict:from_list([{a, 1}, {b, 2}]).
[{a,1},{b,2}]
2> OrdDict2 = orddict:from_list([{b, 7}, {c, 8}]).
[{b,7},{c,8}]
3> orddict:merge(fun (K, V1, V2) -> V1 * V2 end, OrdDict1, OrdDict2).
[{a,1},{b,14},{c,8}]

Result = orddict(none(), none())

Creates a new dictionary.

Examples

1> orddict:new().
[]

Returns the number of elements in an Orddict.

Examples

1> orddict:size(orddict:new()).
0
2> orddict:size(orddict:from_list([{a,1},{b,2},{c,3}])).
3

Orddict1 = Orddict2 = orddict(Key, Value)

Stores a Key-Value pair in a dictionary.

If the Key already exists in Orddict1, the associated value is replaced by Value.

Examples

1> OrdDict1 = orddict:from_list([{a, 1}, {b, 2}]).
[{a,1},{b,2}]
2> orddict:store(a, 99, OrdDict1).
[{a,99},{b,2}]
3> orddict:store(c, 100, OrdDict1).
[{a,1},{b,2},{c,100}]

Key = Value = term()

Orddict = Orddict1 = orddict(Key, Value)

Result = {Value, Orddict1} | error

This function returns value from dictionary and new dictionary without this value.

Returns error if the key is not present in the dictionary.

Examples

1> OrdDict1 = orddict:from_list([{a, 1}, {b, 2}]).
[{a,1},{b,2}]
2> orddict:take(a, OrdDict1).
{1,[{b,2}]}
3> orddict:take(missing, OrdDict1).
error

List = [{Key, Value}]

Converts a dictionary to a list representation.

Examples

1> OrdDict = orddict:from_list([{2,b},{1,a}]).
[{1,a},{2,b}]
2> orddict:to_list(OrdDict).
[{1,a},{2,b}]

Fun = fun((Value1 :: Value) -> Value2 :: Value)

Orddict1 = Orddict2 = orddict(Key, Value)

Updates a value in a dictionary by calling Fun on the value to get a new value.

An exception is generated if Key is not present in the dictionary.

Examples

1> OrdDict1 = orddict:from_list([{a, 1}, {b, 2}]).
[{a,1},{b,2}]
2> orddict:update(a, fun (V) -> V + 100 end, OrdDict1).
[{a,101},{b,2}]

Fun = fun((Value1 :: Value) -> Value2 :: Value)

Initial = Value

Orddict1 = Orddict2 = orddict(Key, Value)

Updates a value in a dictionary by calling Fun on the value to get a new value.

If Key is not present in the dictionary, Initial is stored as the first value.

For example, append/3 can be defined as follows:

append(Key, Val, D) ->
    update(Key, fun (Old) -> Old ++ [Val] end, [Val], D).

Examples

1> OrdDict1 = orddict:from_list([{a, 1}, {b, 2}]).
[{a,1},{b,2}]
2> OrdDict2 = orddict:update(c, fun (V) -> V + 100 end, 99, OrdDict1).
[{a,1},{b,2},{c,99}]
3> orddict:update(a, fun (V) -> V + 100 end, 99, OrdDict2).
[{a,101},{b,2},{c,99}]

Increment = number()

Orddict1 = Orddict2 = orddict(Key, Value)

Adds Increment to the value associated with Key and store this value.

If Key is not present in the dictionary, Increment is stored as the first value.

Examples

1> OrdDict1 = orddict:from_list([{a,0},{b,0}]).
[{a,0},{b,0}]
2> OrdDict2 = orddict:update_counter(a, 1, OrdDict1).
[{a,1},{b,0}]
3> OrdDict3 = orddict:update_counter(b, 2, OrdDict2).
[{a,1},{b,2}]
4> orddict:update_counter(z, 7, OrdDict3).
[{a,1},{b,2},{z,7}]