How to use map functions? - f#

Question

So I have many types that have been defined and functions which mapped data into these records/types. Now I need to map the contents of each record/type into a "master" record which will contain everything from previous records based on a key which in this case is State. I am not sure how to go about doing this, but I have my attempt down below, along with more code to provide context. Any suggestions? Please comment if you need more information.
I have types that are defined as so:
type StateEdu =
{ State : string
Education : int
Income : float }
type StateFamily =
{ State : string
PctMoreThan4Children : float
PctFamilyMorethan3 : float }
But now I need to do something LIKE THIS (This did not work when I ran it):
let stateall = statemap.Keys
let statedatamap =
stateall
|> Seq.map (fun state ->
state,
{State = state
StateEdu = StateEdu.[state]
StateFamily = StateFamily.[state]
})
|> Map.ofSeq

Answer 1

It's not exactly clear what is your desired output as you're missing both variables and types. Assuming you want a new map/dictionary that contains the key of a state, and then a record which has the both the education state and the family state, one way would be is this:
(I added the types and fixed some errors)
type StateEdu =
{ State : string
Education : int
Income : float }
type StateFamily =
{ State : string
PctMoreThan4Children : float
PctFamilyMorethan3 : float }
//I added this new type so this is value of the final map.
type State2 =
{ State : string
StateEdu : StateEdu
StateFamily : StateFamily }
//Instead providing the csv it's better to minimize the example, so here are the two record lists.
let stateEdu =
[{State = "TX"; Income = 51522.; Education = 0}
{State = "AL"; Income = 6481.; Education = 1}
{State = "MO"; Income = 78921.; Education = 1}
{State = "TN"; Income = 12000.; Education = 4}
{State = "PA"; Income = 79850.; Education = 2}
{State = "NY"; Income = 79215.; Education = 1}
{State = "CA"; Income = 79045.; Education = 2}]
let datafamily =
[{State = "TX"; PctMoreThan4Children = 51.52; PctFamilyMorethan3 = 65.0}
{State = "AL"; PctMoreThan4Children = 64.00; PctFamilyMorethan3 = 51.4}
{State = "MO"; PctMoreThan4Children = 78.92; PctFamilyMorethan3 = 25.1}
{State = "TN"; PctMoreThan4Children = 12.00; PctFamilyMorethan3 = 62.1}
{State = "PA"; PctMoreThan4Children = 8.50; PctFamilyMorethan3 = 41.2}
{State = "NY"; PctMoreThan4Children = 25.15; PctFamilyMorethan3 = 31.0}
{State = "CA"; PctMoreThan4Children = 79.5; PctFamilyMorethan3 = 50.5}]
let stateedu =
stateEdu
|> Seq.map (fun x -> x.State,x)
|> Map.ofSeq
let datafam =
datafamily
|> Seq.map (fun x -> x.State,x)
|> Map.ofSeq
//This is one way to quickly extract the keys
let stateall = stateedu |> Map.toSeq |> Seq.map fst
//We go through all the keys
let statedatamap =
stateall
|> Seq.map (fun state ->
state,
{State = state //this is the State2type
StateEdu = stateedu.[state]
StateFamily = datafam.[state]
})
|> Map.ofSeq
Output:
val statedatamap : Map = map
[("AL", {State = "AL";
StateEdu = {State = "AL";
Education = 1;
Income = 6481.0;};
StateFamily = {State = "AL";
PctMoreThan4Children = 64.0;
PctFamilyMorethan3 = 51.4;};});
("CA", {State = "CA";
StateEdu = {State = "CA";
Education = 2;
Income = 79045.0;};
StateFamily = {State = "CA";
PctMoreThan4Children = 79.5;
PctFamilyMorethan3 = 50.5;};});
("MO", {State = "MO";
StateEdu = {State = "MO";
Education = 1;
Income = 78921.0;};
StateFamily = {State = "MO";
PctMoreThan4Children = 78.92;
PctFamilyMorethan3 = 25.1;};});
("NY", {State = "NY";
StateEdu = {State = "NY";
Education = 1;
Income = 79215.0;};
StateFamily = {State = "NY";
PctMoreThan4Children = 25.15;
PctFamilyMorethan3 = 31.0;};});
("PA", {State = "PA";
StateEdu = {State = "PA";
Education = 2;
Income = 79850.0;};
StateFamily = {State = "PA";
PctMoreThan4Children = 8.5;
PctFamilyMorethan3 = 41.2;};});
("TN", {State = "TN";
StateEdu = {State = "TN";
Education = 4;
Income = 12000.0;};
StateFamily = {State = "TN";
PctMoreThan4Children = 12.0;
PctFamilyMorethan3 = 62.1;};});
("TX", {State = "TX";
StateEdu = {State = "TX";
Education = 0;
Income = 51522.0;};
StateFamily = {State = "TX";
PctMoreThan4Children = 51.52;
PctFamilyMorethan3 = 65.0;};})]
If necessary you can define your output type to include both records as one item. You can always index to the record by statedu.[state].Education for example.