""" Tests column conversion functionality during parsing for all of the parsers defined in parsers.py """ from io import StringIO from dateutil.parser import parse import numpy as np import pytest import pandas as pd from pandas import ( DataFrame, Index, ) import pandas._testing as tm pytestmark = pytest.mark.usefixtures("pyarrow_skip") def test_converters_type_must_be_dict(all_parsers): parser = all_parsers data = """index,A,B,C,D foo,2,3,4,5 """ with pytest.raises(TypeError, match="Type converters.+"): parser.read_csv(StringIO(data), converters=0) @pytest.mark.parametrize("column", [3, "D"]) @pytest.mark.parametrize( "converter", [parse, lambda x: int(x.split("/")[2])] # Produce integer. ) def test_converters(all_parsers, column, converter): parser = all_parsers data = """A,B,C,D a,1,2,01/01/2009 b,3,4,01/02/2009 c,4,5,01/03/2009 """ result = parser.read_csv(StringIO(data), converters={column: converter}) expected = parser.read_csv(StringIO(data)) expected["D"] = expected["D"].map(converter) tm.assert_frame_equal(result, expected) def test_converters_no_implicit_conv(all_parsers): # see gh-2184 parser = all_parsers data = """000102,1.2,A\n001245,2,B""" converters = {0: lambda x: x.strip()} result = parser.read_csv(StringIO(data), header=None, converters=converters) # Column 0 should not be casted to numeric and should remain as object. expected = DataFrame([["000102", 1.2, "A"], ["001245", 2, "B"]]) tm.assert_frame_equal(result, expected) def test_converters_euro_decimal_format(all_parsers): # see gh-583 converters = {} parser = all_parsers data = """Id;Number1;Number2;Text1;Text2;Number3 1;1521,1541;187101,9543;ABC;poi;4,7387 2;121,12;14897,76;DEF;uyt;0,3773 3;878,158;108013,434;GHI;rez;2,7356""" converters["Number1"] = converters["Number2"] = converters[ "Number3" ] = lambda x: float(x.replace(",", ".")) result = parser.read_csv(StringIO(data), sep=";", converters=converters) expected = DataFrame( [ [1, 1521.1541, 187101.9543, "ABC", "poi", 4.7387], [2, 121.12, 14897.76, "DEF", "uyt", 0.3773], [3, 878.158, 108013.434, "GHI", "rez", 2.7356], ], columns=["Id", "Number1", "Number2", "Text1", "Text2", "Number3"], ) tm.assert_frame_equal(result, expected) def test_converters_corner_with_nans(all_parsers): parser = all_parsers data = """id,score,days 1,2,12 2,2-5, 3,,14+ 4,6-12,2""" # Example converters. def convert_days(x): x = x.strip() if not x: return np.nan is_plus = x.endswith("+") if is_plus: x = int(x[:-1]) + 1 else: x = int(x) return x def convert_days_sentinel(x): x = x.strip() if not x: return np.nan is_plus = x.endswith("+") if is_plus: x = int(x[:-1]) + 1 else: x = int(x) return x def convert_score(x): x = x.strip() if not x: return np.nan if x.find("-") > 0: val_min, val_max = map(int, x.split("-")) val = 0.5 * (val_min + val_max) else: val = float(x) return val results = [] for day_converter in [convert_days, convert_days_sentinel]: result = parser.read_csv( StringIO(data), converters={"score": convert_score, "days": day_converter}, na_values=["", None], ) assert pd.isna(result["days"][1]) results.append(result) tm.assert_frame_equal(results[0], results[1]) @pytest.mark.parametrize("conv_f", [lambda x: x, str]) def test_converter_index_col_bug(all_parsers, conv_f): # see gh-1835 , GH#40589 parser = all_parsers data = "A;B\n1;2\n3;4" rs = parser.read_csv( StringIO(data), sep=";", index_col="A", converters={"A": conv_f} ) xp = DataFrame({"B": [2, 4]}, index=Index(["1", "3"], name="A", dtype="object")) tm.assert_frame_equal(rs, xp) def test_converter_identity_object(all_parsers): # GH#40589 parser = all_parsers data = "A,B\n1,2\n3,4" rs = parser.read_csv(StringIO(data), converters={"A": lambda x: x}) xp = DataFrame({"A": ["1", "3"], "B": [2, 4]}) tm.assert_frame_equal(rs, xp) def test_converter_multi_index(all_parsers): # GH 42446 parser = all_parsers data = "A,B,B\nX,Y,Z\n1,2,3" result = parser.read_csv( StringIO(data), header=list(range(2)), converters={ ("A", "X"): np.int32, ("B", "Y"): np.int32, ("B", "Z"): np.float32, }, ) expected = DataFrame( { ("A", "X"): np.int32([1]), ("B", "Y"): np.int32([2]), ("B", "Z"): np.float32([3]), } ) tm.assert_frame_equal(result, expected)