I need to retrieve information from a JsValue that may be structured in a few different ways buy the specific values I'm looking for will always be under similar names.
So for example I could have something like:
{
"name" : "Watership Down",
"location" : {
"lat" : 51.235685,
"long" : -1.309197
}
}
OR
{
"title" : "Watership Down",
"size" : "M",
"location" : {
"latitude" : 51.235685,
"longitude" : -1.309197
}
}
and I'd want to be able to do: val text = json \\ "name"|"title"
I know what I want is either under name or title but not sure which in a given scenario. Is there any way to do something similar to what I did above with an "or" similar to Scala's .getOrElse() method?
You can do:
val text = (json \\ "name").asOpt[String]
.getOrElse((json \\ "title").as[String])
Related
How do I access the JSON array to display the output of "AdjustedScheduleTime" from the Trip section?
I got it working for StopLabel as shown below, but I'm struggling to access AdjustedScheduleTime.
I tried the following:
["GetNextTripsForStopResponse"]["GetNextTripsForStopResult"]["Route"]["RouteDirection"]["Trips"]["Trip"]["AdjustedScheduleTime"]
but doesn't work.
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let parameters = [
"appID": "5rt5rydg", //incorrect appID
"apiKey": "3b5fb15rdgy5454hdrfhr", //incorrect apiKey
"routeNo": "14",
"stopNo": "8600",
"format": "JSON"
]
AF.request("https://api.octranspo1.com/v1.2/GetNextTripsForStop?", method: .post, parameters: parameters,encoding:
URLEncoding.httpBody, headers: nil).responseJSON{ response in
let swiftyJsonVar = JSON(response.result.value!)
print(swiftyJsonVar)
if let busInfo = swiftyJsonVar["GetNextTripsForStopResult"]["StopLabel"].string {
print(": ",busInfo)
print("Label1: ", self.label1.text = busInfo)
}
}
}
This is the results:
{
"GetNextTripsForStopResult" : {
"Error" : "",
"Route" : {
"RouteDirection" : {
"RouteLabel" : "St-Laurent",
"Error" : "",
"RequestProcessingTime" : "20190112151425",
"Trips" : {
"Trip" : [
{
"AdjustmentAge" : "0.38",
"GPSSpeed" : "0.5",
"Latitude" : "45.429457",
"Longitude" : "-75.684117",
"TripDestination" : "St-Laurent",
"LastTripOfSchedule" : false,
"TripStartTime" : "14:31",
"BusType" : "4LB - IN",
"AdjustedScheduleTime" : "11"
},
{
"AdjustmentAge" : "4.32",
"GPSSpeed" : "0.5",
"Latitude" : "45.413749",
"Longitude" : "-75.689748",
"TripDestination" : "St-Laurent",
"LastTripOfSchedule" : false,
"TripStartTime" : "14:46",
"BusType" : "4LB - IN",
"AdjustedScheduleTime" : "22"
},
{
"AdjustmentAge" : "0.55",
"GPSSpeed" : "31.3",
"Latitude" : "45.399587",
"Longitude" : "-75.727631",
"TripDestination" : "St-Laurent",
"LastTripOfSchedule" : false,
"TripStartTime" : "15:01",
"BusType" : "4L - IN",
"AdjustedScheduleTime" : "37"
}
]
},
"RouteNo" : 14,
"Direction" : "Eastbound"
}
},
"StopLabel" : "MCARTHUR \/ IRWIN MILLER",
"StopNo" : "8600"
}
}
: MCARTHUR / IRWIN MILLER //This is the desired output for StopLabel
Ok, so do you explain JSON. Here's a shot.
First some rules:
When you see opening { it means dictionary, you have to pick a key next
When you see opening [ it means array. you have to pick an index
When you see "SomeString": its a key in an array.
Dictionaries have keys, arrays have index. Pick accordingly..
So when we walk through this response:
We see that we start with {. We have a dictionary! We're expecting to see some keys next.
So lets pick a key: We only have one and it's "GetNextTripsForStopResult". so far we have: swiftyJsonVar["GetNextTripsForStopResult"]
We now look at the content of "GetNextTripsForStopResult". We see it's also a dictionary. Again we should have some keys. We do. We have Error, Route, StopLabel and more. Let's pick a key. Since we're trying to get to a "AdjustedScheduleTime", lets pick Route. so far we have ["GetNextTripsForStopResult"]["Route"]
Now lets look at the contents of Route. Its a dictionary again.
Again we pick a key and keep repeating till we hit Trip. You should have ["GetNextTripsForStopResult"]["Route"]["RouteDirection"]["Trips"]["Trip"]
Lets look at what we have in Trip Whats this?..its an array!
We have to pick an index now. We need to chose somehow. Thats the tricky part. In order to do that we need some more information. So lets just ARBITRARILY chose one. Lets take the last one. so we have: ["GetNextTripsForStopResult"]["Route"]["RouteDirection"]["Trips"]["Trip"][2]
Now we can get our final key AdjustedScheduleTime. So let's pick it!
["GetNextTripsForStopResult"]["Route"]["RouteDirection"]["Trips"]["Trip"][2]["AdjustedScheduleTime"]
Keep in mind:
These hard coded indexes are almost NEVER what you want. Maybe you need to show all the AdjustedScheduleTime to the user or let the user chose one, or add all of them up. That really depends on your application and what you're trying to accomplish. I chose the last index (2) arbitrarily without having any knowledge of your application, the api you're calling and what you're trying to achieve. Its VERY possible that you don't want the last index.
I'm having a problem with querying a MongoDB dataset ("On Street Crime in Camden" from data.gov.uk)
The database name is Crime_Data_in_Camden and the collection name is Street_Crime_Camden. The query to find all records, db.Street_Crime_Camden.find(), works fine but anything else returns nothing at
all. Here is a portion of the metadata:
{
"id" : 509935,
"name" : "Ward Name",
"dataTypeName" : "text",
"fieldName" : "ward_name",
"position" : 13,
"renderTypeName" : "text",
"tableColumnId" : 258836,
"width" : 100,
"cachedContents" : {
"largest" : "West Hampstead",
"non_null" : 79813,
"null" : 0,
"top" : [ {
"item" : "Regent's Park",
"count" : 20
}, {
"item" : "Swiss Cottage",
"count" : 19
}, {
"item" : "Holborn and Covent Garden",
"count" : 18
}
}
}
I've tried 3 attempts at a basic query:
db.Street_Crime_Camden.find({"ward_name":"West Hampstead"});
db.Street_Crime_Camden.find({'meta.ward_name':'West Hampstead'});
db.Street_Crime_Camden.find({meta:{ward_name:"West Hampstead"} });
According to any documentation or tutorial that I've seen any of these approaches should be valid. And I know that there are hundreds of rows (or documents) that match those terms, so why are these queries returning nothing? Advice would be appreciated.
The common theme in the three aproaches you tried is some form of ward_name = West Hampstead but there is no attribute named ward_name in the document you shared with us.
Based on the document you show in your question the only way of addressing an attribute with the value West Hampstead is:
db.Street_Crime_Camden.find({"cachedContents.largest": "West Hampstead"});
For background; you address attributes in your documents by using dot notation so the document you included in your question could be found by any of the following find commands:
db.Street_Crime_Camden.find({"name": "Ward Name"});
db.Street_Crime_Camden.find({"position": 13});
db.Street_Crime_Camden.find({"cachedContents.top.item": "Swiss Cottage"});
db.Street_Crime_Camden.find({"cachedContents.top.1.count": 20});
... etc
These examples might help you to understand how to form find criteria. The MongoDB docs are also useful.
I have a data field that looks like this :
{ "field1" : [{"name":'name1',"value1":true},
{"name":'name2',"value2":false}
],
"field2" : [{"name":'name1',"value1":true},
{"name":'name2',"value2":false}
]
}
Is it possible to update a specific field with an update ?
create table t_json (
t_data json
);
insert into t_json values('{"field1":[{"name":"name1","value" : true},{"name":"name2","value" : false}],"field1":[{"name":"name1","value" : true},{"name":"name2","value" : false}]}');
select t_data->'field1'
from t_json;
I tried this :
update t_json
set t_data->'a' = '[{"value1" : true, "value2" : false}]';
But I get an error : "syntax error at or near ->
What is missing ?
I wanted to post this here in case it helps anybody else. By all means use JSON over JSONB unless you actually need features that JSONB affords you. In general, if you need to perform queries on the JSON data itself, use JSONB. If you are just needing to store data, use JSON.
Anyhow, here is how I am updating a JSON[] field:
UPDATE foo SET bar = ARRAY[$${"hello": "world"}$$, $${"baz": "bing"}$$]::JSON[]
The important things to notice are this:
The array is wrapped like this: ARRAY[ ... ]::JSON[]
Each item in the array is wrapped like this: $${ "foo": "bar" }$$
It is worth noting that this same technique can be used for other array types. For example, if you have a text[] column, the query would look like this:
UPDATE foo SET bar = ARRAY[$$hello world$$, $$baz bing$$]::TEXT[]`
Fixing your typos
Doubt it. This is not valid json. name1 and name2 must be double quoted. To ease working with json, ALWAYS use double quotes. ALWAYS query-quote with double-dollar.
{ "field1" : [{"name":'name1',"value1":true},
{"name":'name2',"value2":false}
],
"field2" : [{"name":'name1',"value1":true},
{"name":'name2',"value2":false}
]
}
And, what you INSERTED is also funky.. ALWAYS paste beautified valid JSON in your question.
{
"field1":[{"name":"name1","value" : true},{"name":"name2","value" : false}],
"field1":[{"name":"name1","value" : true},{"name":"name2","value" : false}]
}
Let's change that and fix it.
{
"field1":[{"name":"name1","value" : true},{"name":"name2","value" : false}],
"field2":[{"name":"name1","value" : true},{"name":"name2","value" : false}]
}
Now let's put it in a query..
TRUNCATE t_json;
INSERT INTO t_json (t_data) VALUES ($$
{
"field1":[{"name":"name1","value" : true},{"name":"name2","value" : false}],
"field2":[{"name":"name1","value" : true},{"name":"name2","value" : false}]
}
$$);
Making the update of the JSON
Now it works.. Now you can update it as you want..
UPDATE t_json
SET t_data = jsonb_set(
t_data::jsonb,
'{field1}',
$${"whatever":1}$$
);
Change from JSON to JSONB
Notice we're having to cast to jsonb. As a general rule, NEVER use JSON (not everyone agrees, see comments). There is no point. Instead use the newer JSONB.
ALTER TABLE t_json ALTER COLUMN t_data TYPE jsonb ;
Now you can do
UPDATE t_json
SET t_data = jsonb_set(
t_data,
'{field1}',
$${"whatever":1}$$
);
I have nested JSON like -
"disks" : [ {
"name" : "v2.16",
"diskAggregate" : "aggr0",
"diskRPM" : 15000,
"totalSizeBytes" : 1077477376,
"vendorId" : "NETAPP ",
"usedBytes" : 1070071808,
"diskType" : "FCAL",
"uuid" : "4E455441:50502020:56442D31:3030304D:422D465A:2D353230:32353836:30303030:00000000:00000000",
"portName" : "FC:A ",
"raidGroup" : "rg0"
},
{
"name" : "v4.16",
"diskAggregate" : "aggr0",
"diskRPM" : 15000,
"totalSizeBytes" : 1077477376,
"vendorId" : "NETAPP ",
"usedBytes" : 1070071808,
"diskType" : "FCAL",
"uuid" : "4E455441:50502020:56442D31:3030304D:422D465A:2D353230:32353633:34333030:00000000:00000000",
"portName" : "FC:B ",
"raidGroup" : "rg0"
}]
I want to get addition 'totalSizeBytes' from above list of objects.
I used following code to get it -
val storageDevices = "above given json".toList
val totalCapacity = storageDevices.foldLeft(0) {
case (sumOfAllDevices, storageDevice) =>
val sumOfTotalBytesOnStorageDevice = storageDevice.disks.foldLeft(0) {
case (totalBytesOnDevice, disk) =>
totalBytesOnDevice + disk.usedBytes.getOrElse(0).toString.toInt
}
sumOfAllDevices + sumOfTotalBytesOnStorageDevice
// Logger.info("dss"+sumOfTotalBytesOnStorageDevice.toString.toInt)
}
This code gives me total capacity in Integer format. But as there are too many objects in disks array, the totalCapacity will get exceed int. So I wanted to convert it to Long while doing addition.
I want following output-
"totalCapacity": [
{
"name": "192.168.20.22",
"y": 123456789
}
]
How do I convert it to Long to get exact sum of all 'totalBytesAvailable' from array/list???
Cast zero values as 0L (by default assumed Int), both in foldLeft(0L) and in getOrElse(0L), so the compiler will enforce arithmetic additions on Long.
I have a rather complex structure on my json and I cannot find how to query it to get the rows I am interested in. Here is a sample of my data:
{
"_id" : ObjectId("5282bf9ce4b05216ca1b68f8"),
"authorID" : ObjectId("5282a8c3e4b0d7f4f4d07b9a"),
"blogID" : "7180831558698033600",
"blogs" : {
"$" : {
"posts" : [
[
{
"author" : {
"displayName" : "mms",
...
...
...
}}}
So, I am interested in finding all json entries that have the author displayName equal to "mms".
My collection name is bz so, a find all query would be: db.dz.find()
What criteria do I have to put inside the find() to only get json document with author displayName equal to mms?
Any ideas?
Thank you in advance!
Suppose you have replaced field name "$" with "dollarSign".
Then db.dz.find({"blogs.dollarSign.posts.author.displayName": "mms"}) will fetch whole documents according to your requirements.