F# group by more than one value and aggregate
F#. I have a list transactions of the following type:
type Transaction(Debitor: string, Spend:float, Creditor:string) =
member this.Debitor = Debitor
member this.Spend = Spend
member this.Creditor = Creditor
I know how to group by one value. Say for example I want to group per property Debitor, it's easy to use that property as the Key of the group:
let tsGroupDebitor =
transactions
|> Seq.groupBy(fun ts -> ts.Debitor)
However, I cannot manage to group per two values, say Debitor and Creditor. Ideally, I would like to group considering Debitor AND Creditor, while appling an aggregator function "Sum" for the Spend property.
In other words, I'd like to achieve the F# equivalent of the following LINQ query:
var transactions_GroupSameDebitorCreditor =
transactions
.GroupBy(ts => new { ts.Debitor, ts.Creditor }) // group by multiple values
.Select(gr => new
{
Debitor = gr.Key.Debitor,
Debit = gr.Sum(trans => trans.Spend), //sum the trans values per grouped relationships
Creditor = gr.Key.Creditor
});
Where a IEnumerable of anonymous type was returned.
c# linq f# grouping
asked Nov 24 '18 at 17:21
alexlomba87alexlomba87
182313
add a comment |
F#. I have a list transactions of the following type:
type Transaction(Debitor: string, Spend:float, Creditor:string) =
member this.Debitor = Debitor
member this.Spend = Spend
member this.Creditor = Creditor
I know how to group by one value. Say for example I want to group per property Debitor, it's easy to use that property as the Key of the group:
let tsGroupDebitor =
transactions
|> Seq.groupBy(fun ts -> ts.Debitor)
However, I cannot manage to group per two values, say Debitor and Creditor. Ideally, I would like to group considering Debitor AND Creditor, while appling an aggregator function "Sum" for the Spend property.
In other words, I'd like to achieve the F# equivalent of the following LINQ query:
var transactions_GroupSameDebitorCreditor =
transactions
.GroupBy(ts => new { ts.Debitor, ts.Creditor }) // group by multiple values
.Select(gr => new
{
Debitor = gr.Key.Debitor,
Debit = gr.Sum(trans => trans.Spend), //sum the trans values per grouped relationships
Creditor = gr.Key.Creditor
});
Where a IEnumerable of anonymous type was returned.
c# linq f# grouping
asked Nov 24 '18 at 17:21
alexlomba87alexlomba87
182313
add a comment |
F#. I have a list transactions of the following type:
type Transaction(Debitor: string, Spend:float, Creditor:string) =
member this.Debitor = Debitor
member this.Spend = Spend
member this.Creditor = Creditor
I know how to group by one value. Say for example I want to group per property Debitor, it's easy to use that property as the Key of the group:
let tsGroupDebitor =
transactions
|> Seq.groupBy(fun ts -> ts.Debitor)
However, I cannot manage to group per two values, say Debitor and Creditor. Ideally, I would like to group considering Debitor AND Creditor, while appling an aggregator function "Sum" for the Spend property.
In other words, I'd like to achieve the F# equivalent of the following LINQ query:
var transactions_GroupSameDebitorCreditor =
transactions
.GroupBy(ts => new { ts.Debitor, ts.Creditor }) // group by multiple values
.Select(gr => new
{
Debitor = gr.Key.Debitor,
Debit = gr.Sum(trans => trans.Spend), //sum the trans values per grouped relationships
Creditor = gr.Key.Creditor
});
Where a IEnumerable of anonymous type was returned.
c# linq f# grouping
asked Nov 24 '18 at 17:21
alexlomba87alexlomba87
182313
F#. I have a list transactions of the following type:
type Transaction(Debitor: string, Spend:float, Creditor:string) =
member this.Debitor = Debitor
member this.Spend = Spend
member this.Creditor = Creditor
I know how to group by one value. Say for example I want to group per property Debitor, it's easy to use that property as the Key of the group:
let tsGroupDebitor =
transactions
|> Seq.groupBy(fun ts -> ts.Debitor)
However, I cannot manage to group per two values, say Debitor and Creditor. Ideally, I would like to group considering Debitor AND Creditor, while appling an aggregator function "Sum" for the Spend property.
In other words, I'd like to achieve the F# equivalent of the following LINQ query:
var transactions_GroupSameDebitorCreditor =
transactions
.GroupBy(ts => new { ts.Debitor, ts.Creditor }) // group by multiple values
.Select(gr => new
{
Debitor = gr.Key.Debitor,
Debit = gr.Sum(trans => trans.Spend), //sum the trans values per grouped relationships
Creditor = gr.Key.Creditor
});
Where a IEnumerable of anonymous type was returned.
c# linq f# grouping
c# linq f# grouping
asked Nov 24 '18 at 17:21
alexlomba87alexlomba87
182313
asked Nov 24 '18 at 17:21
alexlomba87alexlomba87
182313
edited Nov 24 '18 at 18:16
alexlomba87
asked Nov 24 '18 at 17:21
alexlomba87alexlomba87
182313
asked Nov 24 '18 at 17:21
alexlomba87alexlomba87
182313
asked Nov 24 '18 at 17:21
alexlomba87alexlomba87
182313
182313
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
You can use a tuple as the group key like this:
let tsGroupDebitor =
transactions
|> Seq.groupBy(fun ts -> (ts.Debitor, ts.Creditor))
If you want to aggregate the transactions of each group to sum the Spend property, you can do it like this:
let tsGroupDebitor =
transactions
|> Seq.groupBy(fun ts -> (ts.Debitor, ts.Creditor))
|> Seq.map(fun ((debitor, creditor), values) -> ( debitor, creditor, values |> Seq.sumBy (fun t -> t.Spend)))
Notice how I use pattern matching with the pattern ((debitor, creditor), values) to be able to access the two parts of the group key and the sequence of transactions for each group (values)
answered Nov 24 '18 at 17:30
Yacoub MassadYacoub Massad
23.7k21942
I see. So the last pipeline operator|> Seq.sumBy (fun t -> t.Spend)is applied only tovaluesin order to sum only theSpendproperty, and thesumBymethod is used to specify a function, which you couldn't with thesummethod. Very useful, thank you.
– alexlomba87
Nov 24 '18 at 18:09
1
sumByis a useful shortcut. You can dovalues |> Seq.map (fun t -> t.Spend) |> Seq.suminstead if you want to.
– Yacoub Massad
Nov 24 '18 at 18:28
add a comment |
let sumTransactions (transactions: Transaction list) =
transactions
|> Seq.groupBy(fun ts -> (ts.Creditor, ts.Debitor))
|> Seq.map (fun ((cred, deb), ts) ->
let s = ts |> Seq.sumBy (fun t -> t.Spend)
Transaction(deb, s , cred))
answered Nov 24 '18 at 17:32
LeeLee
120k14175245
add a comment |
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2 Answers
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active
oldest
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2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
You can use a tuple as the group key like this:
let tsGroupDebitor =
transactions
|> Seq.groupBy(fun ts -> (ts.Debitor, ts.Creditor))
If you want to aggregate the transactions of each group to sum the Spend property, you can do it like this:
let tsGroupDebitor =
transactions
|> Seq.groupBy(fun ts -> (ts.Debitor, ts.Creditor))
|> Seq.map(fun ((debitor, creditor), values) -> ( debitor, creditor, values |> Seq.sumBy (fun t -> t.Spend)))
Notice how I use pattern matching with the pattern ((debitor, creditor), values) to be able to access the two parts of the group key and the sequence of transactions for each group (values)
answered Nov 24 '18 at 17:30
Yacoub MassadYacoub Massad
23.7k21942
I see. So the last pipeline operator|> Seq.sumBy (fun t -> t.Spend)is applied only tovaluesin order to sum only theSpendproperty, and thesumBymethod is used to specify a function, which you couldn't with thesummethod. Very useful, thank you.
– alexlomba87
Nov 24 '18 at 18:09
1
sumByis a useful shortcut. You can dovalues |> Seq.map (fun t -> t.Spend) |> Seq.suminstead if you want to.
– Yacoub Massad
Nov 24 '18 at 18:28
add a comment |
You can use a tuple as the group key like this:
let tsGroupDebitor =
transactions
|> Seq.groupBy(fun ts -> (ts.Debitor, ts.Creditor))
If you want to aggregate the transactions of each group to sum the Spend property, you can do it like this:
let tsGroupDebitor =
transactions
|> Seq.groupBy(fun ts -> (ts.Debitor, ts.Creditor))
|> Seq.map(fun ((debitor, creditor), values) -> ( debitor, creditor, values |> Seq.sumBy (fun t -> t.Spend)))
Notice how I use pattern matching with the pattern ((debitor, creditor), values) to be able to access the two parts of the group key and the sequence of transactions for each group (values)
answered Nov 24 '18 at 17:30
Yacoub MassadYacoub Massad
23.7k21942
I see. So the last pipeline operator|> Seq.sumBy (fun t -> t.Spend)is applied only tovaluesin order to sum only theSpendproperty, and thesumBymethod is used to specify a function, which you couldn't with thesummethod. Very useful, thank you.
– alexlomba87
Nov 24 '18 at 18:09
1
sumByis a useful shortcut. You can dovalues |> Seq.map (fun t -> t.Spend) |> Seq.suminstead if you want to.
– Yacoub Massad
Nov 24 '18 at 18:28
add a comment |
You can use a tuple as the group key like this:
let tsGroupDebitor =
transactions
|> Seq.groupBy(fun ts -> (ts.Debitor, ts.Creditor))
If you want to aggregate the transactions of each group to sum the Spend property, you can do it like this:
let tsGroupDebitor =
transactions
|> Seq.groupBy(fun ts -> (ts.Debitor, ts.Creditor))
|> Seq.map(fun ((debitor, creditor), values) -> ( debitor, creditor, values |> Seq.sumBy (fun t -> t.Spend)))
Notice how I use pattern matching with the pattern ((debitor, creditor), values) to be able to access the two parts of the group key and the sequence of transactions for each group (values)
answered Nov 24 '18 at 17:30
Yacoub MassadYacoub Massad
23.7k21942
You can use a tuple as the group key like this:
let tsGroupDebitor =
transactions
|> Seq.groupBy(fun ts -> (ts.Debitor, ts.Creditor))
If you want to aggregate the transactions of each group to sum the Spend property, you can do it like this:
let tsGroupDebitor =
transactions
|> Seq.groupBy(fun ts -> (ts.Debitor, ts.Creditor))
|> Seq.map(fun ((debitor, creditor), values) -> ( debitor, creditor, values |> Seq.sumBy (fun t -> t.Spend)))
Notice how I use pattern matching with the pattern ((debitor, creditor), values) to be able to access the two parts of the group key and the sequence of transactions for each group (values)
answered Nov 24 '18 at 17:30
Yacoub MassadYacoub Massad
23.7k21942
edited Nov 24 '18 at 17:43
answered Nov 24 '18 at 17:30
Yacoub MassadYacoub Massad
23.7k21942
answered Nov 24 '18 at 17:30
Yacoub MassadYacoub Massad
23.7k21942
answered Nov 24 '18 at 17:30
Yacoub MassadYacoub Massad
23.7k21942
23.7k21942
I see. So the last pipeline operator|> Seq.sumBy (fun t -> t.Spend)is applied only tovaluesin order to sum only theSpendproperty, and thesumBymethod is used to specify a function, which you couldn't with thesummethod. Very useful, thank you.
– alexlomba87
Nov 24 '18 at 18:09
1
sumByis a useful shortcut. You can dovalues |> Seq.map (fun t -> t.Spend) |> Seq.suminstead if you want to.
– Yacoub Massad
Nov 24 '18 at 18:28
add a comment |
I see. So the last pipeline operator|> Seq.sumBy (fun t -> t.Spend)is applied only tovaluesin order to sum only theSpendproperty, and thesumBymethod is used to specify a function, which you couldn't with thesummethod. Very useful, thank you.
– alexlomba87
Nov 24 '18 at 18:09
1
sumByis a useful shortcut. You can dovalues |> Seq.map (fun t -> t.Spend) |> Seq.suminstead if you want to.
– Yacoub Massad
Nov 24 '18 at 18:28
I see. So the last pipeline operator
|> Seq.sumBy (fun t -> t.Spend) is applied only to values in order to sum only the Spend property, and the sumBy method is used to specify a function, which you couldn't with the sum method. Very useful, thank you.– alexlomba87
Nov 24 '18 at 18:09
I see. So the last pipeline operator
|> Seq.sumBy (fun t -> t.Spend) is applied only to values in order to sum only the Spend property, and the sumBy method is used to specify a function, which you couldn't with the sum method. Very useful, thank you.– alexlomba87
Nov 24 '18 at 18:09
1
1
sumBy is a useful shortcut. You can do values |> Seq.map (fun t -> t.Spend) |> Seq.sum instead if you want to.– Yacoub Massad
Nov 24 '18 at 18:28
sumBy is a useful shortcut. You can do values |> Seq.map (fun t -> t.Spend) |> Seq.sum instead if you want to.– Yacoub Massad
Nov 24 '18 at 18:28
add a comment |
let sumTransactions (transactions: Transaction list) =
transactions
|> Seq.groupBy(fun ts -> (ts.Creditor, ts.Debitor))
|> Seq.map (fun ((cred, deb), ts) ->
let s = ts |> Seq.sumBy (fun t -> t.Spend)
Transaction(deb, s , cred))
answered Nov 24 '18 at 17:32
LeeLee
120k14175245
add a comment |
let sumTransactions (transactions: Transaction list) =
transactions
|> Seq.groupBy(fun ts -> (ts.Creditor, ts.Debitor))
|> Seq.map (fun ((cred, deb), ts) ->
let s = ts |> Seq.sumBy (fun t -> t.Spend)
Transaction(deb, s , cred))
answered Nov 24 '18 at 17:32
LeeLee
120k14175245
add a comment |
let sumTransactions (transactions: Transaction list) =
transactions
|> Seq.groupBy(fun ts -> (ts.Creditor, ts.Debitor))
|> Seq.map (fun ((cred, deb), ts) ->
let s = ts |> Seq.sumBy (fun t -> t.Spend)
Transaction(deb, s , cred))
answered Nov 24 '18 at 17:32
LeeLee
120k14175245
let sumTransactions (transactions: Transaction list) =
transactions
|> Seq.groupBy(fun ts -> (ts.Creditor, ts.Debitor))
|> Seq.map (fun ((cred, deb), ts) ->
let s = ts |> Seq.sumBy (fun t -> t.Spend)
Transaction(deb, s , cred))
answered Nov 24 '18 at 17:32
LeeLee
120k14175245
answered Nov 24 '18 at 17:32
LeeLee
120k14175245
answered Nov 24 '18 at 17:32
LeeLee
120k14175245
answered Nov 24 '18 at 17:32
LeeLee
120k14175245
120k14175245
add a comment |
add a comment |
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