Related
Title: How do I dynamically name a collection?
Pseudo-code: collect(n) AS :Label
The primary purpose of this is for easy reading of the properties in the API Server (node application).
Verbose example:
MATCH (user:User)--(n)
WHERE n:Movie OR n:Actor
RETURN user,
CASE
WHEN n:Movie THEN "movies"
WHEN n:Actor THEN "actors"
END as type, collect(n) as :type
Expected output in JSON:
[{
"user": {
....
},
"movies": [
{
"_id": 1987,
"labels": [
"Movie"
],
"properties": {
....
}
}
],
"actors:" [ .... ]
}]
The closest I've gotten is:
[{
"user": {
....
},
"type": "movies",
"collect(n)": [
{
"_id": 1987,
"labels": [
"Movie"
],
"properties": {
....
}
}
]
}]
The goal is to be able to read the JSON result with ease like so:
neo4j.cypher.query(statement, function(err, results) {
for result of results
var user = result.user
var movies = result.movies
}
Edit:
I apologize for any confusion in my inability to correctly name database semantics.
I'm wondering if it's enough just to output the user and their lists of both actors and movies, rather than trying to do a more complicated means of matching and combining both.
MATCH (user:User)
OPTIONAL MATCH (user)--(m:Movie)
OPTIONAL MATCH (user)--(a:Actor)
RETURN user, COLLECT(m) as movies, COLLECT(a) as actors
This query should return each User and his/her related movies and actors (in separate collections):
MATCH (user:User)--(n)
WHERE n:Movie OR n:Actor
RETURN user,
REDUCE(s = {movies:[], actors:[]}, x IN COLLECT(n) |
CASE WHEN x:Movie
THEN {movies: s.movies + x, actors: s.actors}
ELSE {movies: s.movies, actors: s.actors + x}
END) AS types;
As far as a dynamic solution to your question, one that will work with any node connected to your user, there are a few options, but I don't believe you can get the column names to be dynamic like this, or even the names of the collections returned, though we can associate them with the type.
MATCH (user:User)--(n)
WITH user, LABELS(n) as type, COLLECT(n) as nodes
WITH user, {type:type, nodes:nodes} as connectedNodes
RETURN user, COLLECT(connectedNodes) as connectedNodes
Or, if you prefer working with multiple rows, one row each per node type:
MATCH (user:User)--(n)
WITH user, LABELS(n) as type, COLLECT(n) as collection
RETURN user, {type:type, data:collection} as connectedNodes
Note that LABELS(n) returns a list of labels, since nodes can be multi-labeled. If you are guaranteed that every interested node has exactly one label, then you can use the first element of the list rather than the list itself. Just use LABELS(n)[0] instead.
You can dynamically sort nodes by label, and then convert to the map using the apoc library:
WITH ['Actor','Movie'] as LBS
// What are the nodes we need:
MATCH (U:User)--(N) WHERE size(filter(l in labels(N) WHERE l in LBS))>0
WITH U, LBS, N, labels(N) as nls
UNWIND nls as nl
// Combine the nodes on their labels:
WITH U, LBS, N, nl WHERE nl in LBS
WITH U, nl, collect(N) as RELS
WITH U, collect( [nl, RELS] ) as pairs
// Convert pairs "label - values" to the map:
CALL apoc.map.fromPairs(pairs) YIELD value
RETURN U as user, value
Using Power Query in Microsoft Excel 2013, I created a table that looks like this:
// To insert this in Power Query, append a '=' before the 'Table.FromRows'
Table.FromRows(
{
{"0", "Tom", "null", "null"},
{"1", "Bob", [ name="Berlin" , street="BarStreet" ], [ name="Mary", age=25 ]},
{"2", "Jim", [ name="Hamburg", street="FooStreet" ], [ name="Marta", age=30 ]}
},
{"ID", "Name", "Address", "Wife"}
)
Now, I want to expand the columns Address and Wife by using the name attribute
on both records. Manually, I would do it like this:
// To insert this in Power Query, append a '=' before the 'Table.FromRows'
let
t = Table.FromRows(
{
{"0", "Tom", "null", "null"},
{"1", "Bob", [ name="Berlin" , street="BarStreet" ], [ name="Mary", age=25 ]},
{"2", "Jim", [ name="Hamburg", street="FooStreet" ], [ name="Marta", age=30 ]}
},
{"ID", "Name", "Address", "Wife"}
),
expAddress = Table.ExpandRecordColumn(t, "Address", {"name"}, {"Address → name"}),
expWife = Table.ExpandRecordColumn(expAddress, "Wife", {"name"}, {"Wife → name"})
in
expWife
Background
Whenever I have data tables that have a different layout, I need to rewrite the
query. In a fantasy world, you could expand all columns that have Records in
them using a specific key. Ideally, you would have the following library
functions:
// Returns a list with the names of the columns that match the secified type.
// Will also try to infer the type of a column if the table is untyped.
Table.ColumnsOfTypeInfer(
table as table,
listOfTypes as list
) as list
// Expands a column of records into columns with each of the values.
Table.ExpandRecordColumnByKey(
table as table,
columns as list,
key as text,
) as table
Then, I could call
// To insert this in Power Query, append a '=' before the 'Table.FromRows'
let
t = Table.FromRows(
{
{"0", "Tom", "null", "null"},
{"1", "Bob", [ name="Berlin" , street="BarStreet" ], [ name="Mary", age=25 ]},
{"2", "Jim", [ name="Hamburg", street="FooStreet" ], [ name="Marta", age=30 ]}
},
{"ID", "Name", "Address", "Wife"}
),
recordColumns = Table.ColumnsOfTypeInfer(t, {type record}),
expAll = Table.ExpandRecordColumnByKey(t, recordColumns, "name")
in
expAll
Question
Can you get a list of columns with a specific type that is not specified in the table, aka infer it?
Can you make that record expansion generic?
Edit: Added row #0 with two null cells.
(First off, thanks for the clear explanation and sample data and suggestions!)
1) There's no way in M code to do type inference. This limitation might almost be considered a "feature", because if the source data changes in a way that causes the inferred type to be different, it will almost certainly break your query.
Once you load your untyped data, it should be quick to use the Detect Data Type button to generate the M for this. Or if you are reading data from JSON it should be mostly typed enough already.
If you have a specific scenario where this doesn't work want to update your question? :)
2) It's very possible and only a little convoluted to make the record expansion generic, as long as the cell values of the table are records. This finds columns where all rows are either null or a record and expands the name column.
Here's some simple implementations you can add to your library:
let
t = Table.FromRows(
{
{"0", "Tom", null, null},
{"1", "Bob", [ name="Berlin" , street="BarStreet" ], [ name="Mary", age=25 ]},
{"2", "Jim", [ name="Hamburg", street="FooStreet" ], [ name="Marta", age=30 ]}
},
{"ID", "Name", "Address", "Wife"}
),
Table.ColumnsOfAllRowType = (table as table, typ as type) as list => let
ColumnNames = Table.ColumnNames(table),
ColumnsOfType = List.Select(ColumnNames, (name) =>
List.AllTrue(List.Transform(Table.Column(table, name), (cell) => Type.Is(Value.Type(cell), typ))))
in
ColumnsOfType,
Table.ExpandRecordColumnByKey = (table as table, columns as list, key as text) as table =>
List.Accumulate(columns, table, (state, columnToExpand) =>
Table.ExpandRecordColumn(state, columnToExpand, {key}, { columnToExpand & " → " & key })),
recordColumns = Table.ColumnsOfAllRowType(t, type nullable record),
expAll = Table.ExpandRecordColumnByKey(t, recordColumns, "name")
in
expAll
If a new library function can be implemented in just M we're less likely to add it to our standard library, but if you feel it is missing feel free to suggest it at: https://ideas.powerbi.com/forums/265200-power-bi/
You might have a good argument for adding something like Table.ReplaceTypeFromFirstRow(table as table) as table, because constructing the type with M is very messy.
Sorry to come to this a bit late, but I just had a similar challenge. I tried using Chris Webb's ExpandAll function:
http://blog.crossjoin.co.uk/2014/05/21/expanding-all-columns-in-a-table-in-power-query/
... but that only works on Table-type columns, not Record-type columns, but I have managed to hack it to that purpose. I duplicated Chris' function as "ExpandAllRecords" and made 3 edits: :
replaced each if _ is table then Table.ColumnNames(_) with each if _ is record then Record.FieldNames(_)
replaced Table.ExpandTableColumn with Table.ExpandRecordColumn
replaced ExpandAll with ExpandAllRecords
I tried getting both tables and records expanding in one function, but I kept getting type errors.
Anyway, with that in place, the final query is just:
let
t = Table.FromRows(
{
{"1", "Tom", null, [ name="Jane", age=35 ]},
{"2", "Bob", [ name="Berlin" , street="BarStreet" ], [ name="Mary", age=25 ]},
{"3", "Jim", [ name="Hamburg", street="FooStreet" ], [ name="Marta", age=30 ]}
},
{"ID", "Name", "Address", "Wife"}
),
Output = ExpandAllRecords(t)
in
Output
Edit:
Out of concern that that one day the great snippet (by Chris Webb, mentioned by #MikeHoney) will one day disappear), I'll mirror the entire code here:
let
//Define function taking two parameters - a table and an optional column number
Source = (TableToExpand as table, optional ColumnNumber as number) =>
let
//If the column number is missing, make it 0
ActualColumnNumber = if (ColumnNumber=null) then 0 else ColumnNumber,
//Find the column name relating to the column number
ColumnName = Table.ColumnNames(TableToExpand){ActualColumnNumber},
//Get a list containing all of the values in the column
ColumnContents = Table.Column(TableToExpand, ColumnName),
//Iterate over each value in the column and then
//If the value is of type table get a list of all of the columns in the table
//Then get a distinct list of all of these column names
ColumnsToExpand = List.Distinct(List.Combine(List.Transform(ColumnContents,
each if _ is table then Table.ColumnNames(_) else {}))),
//Append the original column name to the front of each of these column names
NewColumnNames = List.Transform(ColumnsToExpand, each ColumnName & "." & _),
//Is there anything to expand in this column?
CanExpandCurrentColumn = List.Count(ColumnsToExpand)>0,
//If this column can be expanded, then expand it
ExpandedTable = if CanExpandCurrentColumn
then
Table.ExpandTableColumn(TableToExpand, ColumnName,
ColumnsToExpand, NewColumnNames)
else
TableToExpand,
//If the column has been expanded then keep the column number the same, otherwise add one to it
NextColumnNumber = if CanExpandCurrentColumn then ActualColumnNumber else ActualColumnNumber+1,
//If the column number is now greater than the number of columns in the table
//Then return the table as it is
//Else call the ExpandAll function recursively with the expanded table
OutputTable = if NextColumnNumber>(Table.ColumnCount(ExpandedTable)-1)
then
ExpandedTable
else
ExpandAll(ExpandedTable, NextColumnNumber)
in
OutputTable
in
Source
You can then use this function on the XML file as follows:
let
//Load XML file
Source = Xml.Tables(File.Contents("C:\Users\Chris\Documents\PQ XML Expand All Demo.xml")),
ChangedType = Table.TransformColumnTypes(Source,{{"companyname", type text}}),
//Call the ExpandAll function to expand all columns
Output = ExpandAll(ChangedType)
in
Output
(Source and downloadable example: Chris Webb's Bi Blog, 2014-05-21)
I need to find and update a number of records in a Rails 3.2, Ruby 2 application. The following code successfully finds the records I want. What I need to do though is add " x" (including the space) to the email address of every user and I can't figure out how to do it.
This finds the records
User.joins(:account)
.where("users.account_id NOT IN (?)", [1955, 3083, 3869])
.where("accounts.partner_id IN (?)", [23,50])
.where("users.staff = '0'")
.where("users.admin = '0'")
.where("users.api_user = '0'")
.where("users.partner_id is null")
.update_all(email: :email.to_s << " X")
but it's the last line I'm having problems with. Is this possible, or do I need to find the records another way?
The update_all method updates a collection of records, but unless you write your own SQL expression, it can only set one value. For example, if you wanted to overwrite all the email addresses with "X", you could do it easily:
User.joins(:account)
.where("users.account_id NOT IN (?)", [1955, 3083, 3869])
# ...other scopes...
.update_all(email: "X")
In your case, what you really need to do is make individual updates to all these records. One way to do it is to find the records, then loop over them and update them one at a time:
users_to_update = User.joins(:account)
.where("users.account_id NOT IN (?)", [1955, 3083, 3869])
.where("accounts.partner_id IN (?)", [23,50])
.where("users.staff = '0'")
.where("users.admin = '0'")
.where("users.api_user = '0'")
.where("users.partner_id is null")
users_to_update.each do |user|
user.update_attribute(:email, "#{user.email} X")
end
Another solution would be to use a SQL expression with update_all, as in Zoran's answer.
Try writing the last line like so:
.update_all("email = email || ' X'")
This uses SQL's string concatenation operator to append the X to the end of the emails.
Hope that helps!
I'm using elasticsearch to get a mapping of ids to some values, but it is crucial that I keep the order of the results in the order that the ids have.
Example:
def term_mapping(ids)
ids = ids.split(',')
self.search do |s|
s.filter :terms, id: ids
end
end
res = term_mapping("4,2,3,1")
The result collection should contain the objects with the ids in order 4,2,3,1...
Do you have any idea how I can achieve this?
If you need to use search you can sort ids before you send them to elasticsearch and retrive results sorted by id, or you can create a custom sort script that will return the position of the current document in the array of ids. However, a simpler and faster solution would be to simply use Multi-Get instead of search.
One option is to use the Multi GET API. If this doesn't work for you, another solution is to sort the results after you retrieve them from es. In python, this can be done this way:
doc_ids = ["123", "333", "456"] # We want to keep this order
order = {v: i for i, v in enumerate(doc_ids)}
es_results = [{"_id": "333"}, {"_id": "456"}, {"_id": "123"}]
results = sorted(es_results, key=lambda x: order[x['_id']])
# Results:
# [{'_id': '123'}, {'_id': '333'}, {'_id': '456'}]
May be this problem is resolved,, but someone will help with this answer
we can used the pinned_query for the ES. Do not need the loop for the sort the order
**qs = {
"size" => drug_ids.count,
"query" => {
"pinned" => {
"ids" => drug_ids,
"organic" => {
"terms": {
"id": drug_ids
}
}
}
}
}**
It will keep the sequence of the input as it
This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
Is it possible to Pivot data using LINQ?
I'm wondering if its at all possible to create crosstab style results with Linq.
I have some data that looks like the following:
var list = new[]
{
new {GroupId = 1, Country = "UK", Value = 10},
new {GroupId = 1, Country = "FR", Value = 12},
new {GroupId = 1, Country = "US", Value = 18},
new {GroupId = 2, Country = "UK", Value = 54},
new {GroupId = 2, Country = "FR", Value = 55},
new {GroupId = 2, Country = "UK", Value = 56}
};
and I'm trying to output to a repeater control something like the following:
GroupId.....UK.....FR.....US
1...........10.....12.....18
2...........54.....55.....56
Its the dynamic columns that are causing my problems. Any solutions to this?
You need a runtimy class to hold these runtimy results. How about xml?
XElement result = new XElement("result",
list.GroupBy(i => i.GroupId)
.Select(g =>
new XElement("Group", new XAttribute("GroupID", g.Key),
g.Select(i => new XAttribute(i.Country, i.Value))
)
)
);
Are you expecting multiple records per result cell? If so there would need to be some Summing (and more grouping) in there.
(this answer is proof of concept, not final result. There's several issues to address, such as: ordering of columns, missing cells, and so on).
After doing a quick search you might want to look at the ModuleBuilder, TypeBuilder, and FieldBuilder classes in System.Reflection.Emit. They allow you to create a class dynamically at runtime. Outside of that you would need to do grouping on your objects and then do something with the hierarchical results you get from LINQ. I am not sure of a way to dynamically create anonymous type fields at runtime, and that sounds like what would need to happen.
You could try using the dynamic linq library provided by MS. They have a number of overloads to extensions methods that take strings as arguments. They also have an expression parser that takes a string an emits a lambda expression. You should be able to create a dynamic select using them.
A word of warning though, you end up with a non-generic IQueryable rather than a generic IQueryable so you are a little bit limited on what you can do with the result, and you give up a bit of type safety, but that may be OK in your application...
The link for the dynamic linq stuff is
http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq-dynamic-query-library.aspx
There is a link where you can download the source code the the dynamic library, plus some nice illustrations of how you can use it.
var labResults = from lab in CoreLabResults
where lab.Patient == 8
group lab by new { lab.Patient, lab.TestNo, lab.CollectedDate }
into labtests
select new
{
labtests.Key.Patient,
labtests.Key.TestNo,
labtests.Key.CollectedDate,
MCHC = labtests.Where(lab => lab.TestVar == "MCHC").FirstOrDefault().Result,
LYABS = labtests.Where(lab => lab.TestVar == "LYABS").FirstOrDefault().Result,
TotalTests = labtests.Count()
}