Merge pull request #865 from econdb/econdb-fix

Econdb fix

Author: bashtage

docs/source/remote_data.rst

@@ -30,6 +30,7 @@ Currently the following sources are supported:
     - :ref:`Tiingo<remote_data.tiingo>`
     - :ref:`IEX<remote_data.iex>`
     - :ref:`Alpha Vantage<remote_data.alphavantage>`
+    - :ref:`Econdb<remote_data.econdb>`
     - :ref:`Enigma<remote_data.enigma>`
     - :ref:`Quandl<remote_data.quandl>`
     - :ref:`St.Louis FED (FRED)<remote_data.fred>`
@@ -298,14 +299,36 @@ Econdb
 official statistical agencies. Free API allows access to the complete
 Econdb database of time series aggregated into datasets.
 
-.. ipython:: python
+Reading data for a single series such as the `RGDP <https://www.econdb.com/series/RGDPUS/>`__
+for United States, is as simple as taking the ticker segment from the URL path
+(``RGDPUS`` in https://www.econdb.com/series/RGDPUS/) and passing it in like:
+
+.. code-block:: ipython
 
     import os
     import pandas_datareader.data as web
 
     f = web.DataReader('ticker=RGDPUS', 'econdb')
     f.head()
 
+The code snippet for exporting the whole dataset, or its filtered down subset,
+can be generated by using the Export -> Pandas Python3 functionality
+on any of the numerous datasets available,
+such as the Eurostat's `GDP and main components <https://www.econdb.com/dataset/NAMQ_10_GDP>`__
+
+.. code-block:: ipython
+
+    import os
+    import pandas_datareader.data as web
+
+    df = web.DataReader('dataset=NAMQ_10_GDP&v=Geopolitical entity (reporting)&h=TIME&from=2018-05-01&to=2021-01-01&GEO=[AL,AT,BE,BA,BG,HR,CY,CZ,DK,EE,EA19,FI,FR,DE,EL,HU,IS,IE,IT,XK,LV,LT,LU,MT,ME,NL,MK,NO,PL,PT,RO,RS,SK,SI,ES,SE,CH,TR,UK]&NA_ITEM=[B1GQ]&S_ADJ=[SCA]&UNIT=[CLV10_MNAC]', 'econdb')
+    df.columns
+
+Datasets can be located through Econdb's `search <https://www.econdb.com/search>`__
+engine, or discovered by exploring the `tree <https://www.econdb.com/tree/>`__
+of available statistical sources.
+
+
 .. _remote_data.econdb:
 
 Enigma

pandas_datareader/econdb.py

@@ -10,6 +10,14 @@ class EcondbReader(_BaseReader):
     _format = None
     _show = "labels"
 
+    def __init__(self, *args, **kwargs):
+        super().__init__(**kwargs)
+        params = dict(s.split("=") for s in self.symbols.split("&"))
+        if "from" in params and not kwargs.get("start"):
+            self.start = pd.to_datetime(params["from"], format="%Y-%m-%d")
+        if "to" in params and not kwargs.get("end"):
+            self.end = pd.to_datetime(params["to"], format="%Y-%m-%d")
+
     @property
     def url(self):
         """API URL"""
@@ -21,7 +29,7 @@ def url(self):
         )
 
     def read(self):
-        """ read one data from specified URL """
+        """read one data from specified URL"""
         results = self.session.get(self.url).json()["results"]
         df = pd.DataFrame({"dates": []}).set_index("dates")
 

pandas_datareader/tests/test_econdb.py

@@ -1,14 +1,28 @@
 import numpy as np
 import pandas as pd
-from pandas import testing as tm
 import pytest
+from pandas import testing as tm
 
 from pandas_datareader import data as web
 
 pytestmark = pytest.mark.stable
 
 
 class TestEcondb(object):
+    def test_infer_start_end_from_symbols(self):
+        df = web.DataReader(
+            (
+                "dataset=NAMQ_10_GDP&v=Geopolitical entity (reporting)"
+                "&h=TIME&from=2010-02-01&to=2018-10-01&GEO=[AL,AT,BE,BA,"
+                "BG,HR,CY,CZ,DK,EE,EA19,FI,FR,DE,EL,HU,IS,IE,IT,XK,LV,LT,"
+                "LU,MT,ME,NL,MK,NO,PL,PT,RO,RS,SK,SI,ES,SE,CH,TR,UK]"
+                "&NA_ITEM=[B1GQ]&S_ADJ=[SCA]&UNIT=[CLV10_MNAC]"
+            ),
+            "econdb",
+        )
+        assert df.index[0].year == 2010
+        assert df.index[-1].year == 2018
+
     def test_get_cdh_e_fos(self):
         # EUROSTAT
         # Employed doctorate holders in non managerial and non professional
@@ -38,7 +52,7 @@ def test_get_tourism(self):
         # TOURISM_INBOUND
 
         df = web.DataReader(
-            "dataset=OE_TOURISM_INBOUND&COUNTRY=JPN,USA&" "VARIABLE=INB_ARRIVALS_TOTAL",
+            "dataset=OE_TOURISM_INBOUND&COUNTRY=JPN,USA&VARIABLE=INB_ARRIVALS_TOTAL",
             "econdb",
             start=pd.Timestamp("2008-01-01"),
             end=pd.Timestamp("2012-01-01"),
@@ -79,7 +93,6 @@ def test_bls(self):
         assert df.loc["2010-05-01"][0] == 217.3
 
     def test_australia_gdp(self):
-
         df = web.DataReader(
             "dataset=ABS_GDP&to=2019-09-01&from=1959-09-01&h=TIME&v=Indicator", "econdb"
         )