Academic Search API

API change history

CalcHistogram

The calchistogram REST API is used to calculate the distribution of attribute values for a set of paper entities.

Try it

Request

Request URL

Request parameters

  • string

    A query expression that specifies the entities over which to calculate histograms.

  • (optional)
    string

    Name of the model that you wish to query. Currently, the value defaults to "latest".

  • (optional)
    string

    A comma delimited list that specifies the attribute values that are included in the response. Attribute names are case-sensitive.

  • (optional)
    number

    Number of results to return.

  • (optional)
    number

    Index of the first result to return.

Request headers

  • string
    Subscription key which provides access to this API. Found in your Profile.

Request body

Responses

200 OK

Response (JSON)

 
NameDescription
expr The expr parameter from the request.
num_entities Total number of matching entities.
histograms An array of histograms, one for each attribute specified in the request.
histograms[x].attribute Name of the attribute over which the histogram was computed.
histograms[x].distinct_values Number of distinct values among matching entities for this attribute.
histograms[x].total_count Total number of value instances among matching entities for this attribute.
histograms[x].histogram Histogram data for this attribute.
histograms[x].histogram[y].value A value for the attribute.
histograms[x].histogram[y].prob Total probability of matching entities with this attribute value.
histograms[x].histogram[y].count Number of matching entities with this attribute value.
aborted True if the request timed out.
 

Representations

{
  "expr": "And(Composite(AA.AuN=='jaime teevan'),Y>2012)",
  "num_entities": 37,
  "histograms": [
    {
      "attribute": "Y",
      "distinct_values": 3,
      "total_count": 37,
      "histogram": [
        {
          "value": 2014,
          "prob": 1.275E-07,
          "count": 15
        },
        {
          "value": 2013,
          "prob": 1.184E-07,
          "count": 12
        },
        {
          "value": 2015,
          "prob": 8.279E-08,
          "count": 10
        }
      ]
    },
    {
      "attribute": "F.FN",
      "distinct_values": 34,
      "total_count": 53,
      "histogram": [
        {
          "value": "crowdsourcing",
          "prob": 7.218E-08,
          "count": 9
        },
        {
          "value": "information retrieval",
          "prob": 4.082E-08,
          "count": 4
        },
        {
          "value": "personalization",
          "prob": 2.384E-08,
          "count": 3
        },
        {
          "value": "mobile search",
          "prob": 2.119E-08,
          "count": 2
        }
      ]
    }
  ]
}

400 Bad Request

Representations

{
  "error": {
    "code": "Bad Argument",
    "message": "The parameter is missing."
  }
}

401 Unauthorized

Representations

{
  "error": {
    "code": "Unspecified",
    "message": "Access denied due to invalid subscription key. Make sure you are subscribed to an API you are trying to call and provide the right key."
  }
}

403 Forbidden

Representations

{
  "error": {
    "code": "QuotaExceeded",
    "message": "Out of call volume quota. Quota will be replenished later."
  }
}

404 Not Found

Representations

{
  "error": {
    "code": "Unspecified",
    "message": "The requested resource is not found."
  }
}

500 Internal Server Error

Representations

{
  "error": {
    "code": "Unspecified",
    "message": "Internal server error."
  }
}

Code samples

@ECHO OFF

curl -v -X GET "https://api.labs.cognitive.microsoft.com/academic/v1.0/calchistogram?expr={expr}?model=latest&attributes={string}&count=10&offset=0"
-H "Ocp-Apim-Subscription-Key: {subscription key}"

--data-ascii "{body}" 
using System;
using System.Net.Http.Headers;
using System.Text;
using System.Net.Http;
using System.Web;

namespace CSHttpClientSample
{
    static class Program
    {
        static void Main()
        {
            MakeRequest();
            Console.WriteLine("Hit ENTER to exit...");
            Console.ReadLine();
        }
        
        static async void MakeRequest()
        {
            var client = new HttpClient();
            var queryString = HttpUtility.ParseQueryString(string.Empty);

            // Request headers
            client.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", "{subscription key}");

            // Request parameters
            queryString["model"] = "latest";
            queryString["attributes"] = "{string}";
            queryString["count"] = "10";
            queryString["offset"] = "0";
            var uri = "https://api.labs.cognitive.microsoft.com/academic/v1.0/calchistogram?expr={expr}&" + queryString;

            var response = await client.GetAsync(uri);
        }
    }
}	
// // This sample uses the Apache HTTP client from HTTP Components (http://hc.apache.org/httpcomponents-client-ga/)
import java.net.URI;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class JavaSample 
{
    public static void main(String[] args) 
    {
        HttpClient httpclient = HttpClients.createDefault();

        try
        {
            URIBuilder builder = new URIBuilder("https://api.labs.cognitive.microsoft.com/academic/v1.0/calchistogram?expr={expr}");

            builder.setParameter("model", "latest");
            builder.setParameter("attributes", "{string}");
            builder.setParameter("count", "10");
            builder.setParameter("offset", "0");

            URI uri = builder.build();
            HttpGet request = new HttpGet(uri);
            request.setHeader("Ocp-Apim-Subscription-Key", "{subscription key}");


            // Request body
            StringEntity reqEntity = new StringEntity("{body}");
            request.setEntity(reqEntity);

            HttpResponse response = httpclient.execute(request);
            HttpEntity entity = response.getEntity();

            if (entity != null) 
            {
                System.out.println(EntityUtils.toString(entity));
            }
        }
        catch (Exception e)
        {
            System.out.println(e.getMessage());
        }
    }
}

<!DOCTYPE html>
<html>
<head>
    <title>JSSample</title>
    <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>
</head>
<body>

<script type="text/javascript">
    $(function() {
        var params = {
            // Request parameters
            "model": "latest",
            "attributes": "{string}",
            "count": "10",
            "offset": "0",
        };
      
        $.ajax({
            url: "https://api.labs.cognitive.microsoft.com/academic/v1.0/calchistogram?expr={expr}&" + $.param(params),
            beforeSend: function(xhrObj){
                // Request headers
                xhrObj.setRequestHeader("Ocp-Apim-Subscription-Key","{subscription key}");
            },
            type: "GET",
            // Request body
            data: "{body}",
        })
        .done(function(data) {
            alert("success");
        })
        .fail(function() {
            alert("error");
        });
    });
</script>
</body>
</html>
#import <Foundation/Foundation.h>

int main(int argc, const char * argv[])
{
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
    
    NSString* path = @"https://api.labs.cognitive.microsoft.com/academic/v1.0/calchistogram?expr={expr}";
    NSArray* array = @[
                         // Request parameters
                         @"entities=true",
                         @"model=latest",
                         @"attributes={string}",
                         @"count=10",
                         @"offset=0",
                      ];
    
    NSString* string = [array componentsJoinedByString:@"&"];
    path = [path stringByAppendingFormat:@"?%@", string];

    NSLog(@"%@", path);

    NSMutableURLRequest* _request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:path]];
    [_request setHTTPMethod:@"GET"];
    // Request headers
    [_request setValue:@"{subscription key}" forHTTPHeaderField:@"Ocp-Apim-Subscription-Key"];
    // Request body
    [_request setHTTPBody:[@"{body}" dataUsingEncoding:NSUTF8StringEncoding]];
    
    NSURLResponse *response = nil;
    NSError *error = nil;
    NSData* _connectionData = [NSURLConnection sendSynchronousRequest:_request returningResponse:&response error:&error];

    if (nil != error)
    {
        NSLog(@"Error: %@", error);
    }
    else
    {
        NSError* error = nil;
        NSMutableDictionary* json = nil;
        NSString* dataString = [[NSString alloc] initWithData:_connectionData encoding:NSUTF8StringEncoding];
        NSLog(@"%@", dataString);
        
        if (nil != _connectionData)
        {
            json = [NSJSONSerialization JSONObjectWithData:_connectionData options:NSJSONReadingMutableContainers error:&error];
        }
        
        if (error || !json)
        {
            NSLog(@"Could not parse loaded json with error:%@", error);
        }
        
        NSLog(@"%@", json);
        _connectionData = nil;
    }
    
    [pool drain];

    return 0;
}
<?php
// This sample uses the Apache HTTP client from HTTP Components (http://hc.apache.org/httpcomponents-client-ga/)
require_once 'HTTP/Request2.php';

$request = new Http_Request2('https://api.labs.cognitive.microsoft.com/academic/v1.0/calchistogram?expr={expr}');
$url = $request->getUrl();

$headers = array(
    // Request headers
    'Ocp-Apim-Subscription-Key' => '{subscription key}',
);

$request->setHeader($headers);

$parameters = array(
    // Request parameters
    'model' => 'latest',
    'attributes' => '{string}',
    'count' => '10',
    'offset' => '0',
);

$url->setQueryVariables($parameters);

$request->setMethod(HTTP_Request2::METHOD_GET);

// Request body
$request->setBody("{body}");

try
{
    $response = $request->send();
    echo $response->getBody();
}
catch (HttpException $ex)
{
    echo $ex;
}

?>
########### Python 2.7 #############
import httplib, urllib, base64

headers = {
    # Request headers
    'Ocp-Apim-Subscription-Key': '{subscription key}',
}

params = urllib.urlencode({
    # Request parameters
    'model': 'latest',
    'attributes': '{string}',
    'count': '10',
    'offset': '0',
})

try:
    conn = httplib.HTTPSConnection('api.labs.cognitive.microsoft.com')
    conn.request("GET", "/academic/v1.0/calchistogram?expr={expr}&%s" % params, "{body}", headers)
    response = conn.getresponse()
    data = response.read()
    print(data)
    conn.close()
except Exception as e:
    print("[Errno {0}] {1}".format(e.errno, e.strerror))

####################################

########### Python 3.2 #############
import http.client, urllib.request, urllib.parse, urllib.error, base64

headers = {
    # Request headers
    'Ocp-Apim-Subscription-Key': '{subscription key}',
}

params = urllib.parse.urlencode({
    # Request parameters
    'model': 'latest',
    'attributes': '{string}',
    'count': '10',
    'offset': '0',
})

try:
    conn = http.client.HTTPSConnection('api.labs.cognitive.microsoft.com')
    conn.request("GET", "/academic/v1.0/calchistogram?expr={expr}&%s" % params, "{body}", headers)
    response = conn.getresponse()
    data = response.read()
    print(data)
    conn.close()
except Exception as e:
    print("[Errno {0}] {1}".format(e.errno, e.strerror))

####################################
require 'net/http'

uri = URI('https://api.labs.cognitive.microsoft.com/academic/v1.0/calchistogram?expr={expr}')

query = URI.encode_www_form({
    # Request parameters
    'model' => 'latest',
    'attributes' => '{string}',
    'count' => '10',
    'offset' => '0'
})
if query.length > 0
  if uri.query && uri.query.length > 0
    uri.query += '&' + query
  else
    uri.query = query
  end
end

request = Net::HTTP::Get.new(uri.request_uri)
# Request headers
request['Ocp-Apim-Subscription-Key'] = '{subscription key}'
# Request body
request.body = "{body}"

response = Net::HTTP.start(uri.host, uri.port, :use_ssl => uri.scheme == 'https') do |http|
    http.request(request)
end

puts response.body