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Fix DataFrame.LoadCsv can not load CSV with duplicate column names #6772

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Merged
merged 3 commits into from
Aug 31, 2023
Merged

Fix DataFrame.LoadCsv can not load CSV with duplicate column names #6772

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375939d
Fix DataFrame.LoadCsv can not load CSV with duplicate column names
asmirnov82 Jul 24, 2023
ecb9114
Merge branch 'main' into 6182_load_csv_duplicate_columns
asmirnov82 Jul 31, 2023
2c72e8c
Merge branch 'main' into 6182_load_csv_duplicate_columns
asmirnov82 Aug 26, 2023
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29 changes: 25 additions & 4 deletions src/Microsoft.Data.Analysis/DataFrame.IO.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
using System.Data.Common;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

Expand Down Expand Up @@ -349,8 +350,8 @@ private static DataFrameColumn CreateColumn(Type kind, string[] columnNames, int
private static DataFrame ReadCsvLinesIntoDataFrame(WrappedStreamReaderOrStringReader wrappedReader,
char separator = ',', bool header = true,
string[] columnNames = null, Type[] dataTypes = null,
long numberOfRowsToRead = -1, int guessRows = 10, bool addIndexColumn = false
)
long numberOfRowsToRead = -1, int guessRows = 10, bool addIndexColumn = false,
bool renameDuplicatedColumns = false)
{
if (dataTypes == null && guessRows <= 0)
{
Expand All @@ -376,6 +377,25 @@ private static DataFrame ReadCsvLinesIntoDataFrame(WrappedStreamReaderOrStringRe
// First pass: schema and number of rows.
while ((fields = parser.ReadFields()) != null)
{
if (renameDuplicatedColumns)
{
var names = new Dictionary<string, int>();

for (int i = 0; i < fields.Length; i++)
{
if (names.TryGetValue(fields[i], out int index))
{
var newName = String.Format("{0}.{1}", fields[i], index);
names[fields[i]] = ++index;
fields[i] = newName;
}
else
{
names.Add(fields[i], 1);
}
}
}

if ((numberOfRowsToRead == -1) || rowline < numberOfRowsToRead)
{
if (linesForGuessType.Count < guessRows || (header && rowline == 0))
Expand Down Expand Up @@ -525,12 +545,13 @@ public static DataFrame LoadCsvFromString(string csvString,
/// <param name="guessRows">number of rows used to guess types</param>
/// <param name="addIndexColumn">add one column with the row index</param>
/// <param name="encoding">The character encoding. Defaults to UTF8 if not specified</param>
/// <param name="renameDuplicatedColumns">If set to true, columns with repeated names are auto-renamed.</param>
/// <returns><see cref="DataFrame"/></returns>
public static DataFrame LoadCsv(Stream csvStream,
char separator = ',', bool header = true,
string[] columnNames = null, Type[] dataTypes = null,
long numberOfRowsToRead = -1, int guessRows = 10, bool addIndexColumn = false,
Encoding encoding = null)
Encoding encoding = null, bool renameDuplicatedColumns = false)
{
if (!csvStream.CanSeek)
{
Expand All @@ -543,7 +564,7 @@ public static DataFrame LoadCsv(Stream csvStream,
}

WrappedStreamReaderOrStringReader wrappedStreamReaderOrStringReader = new WrappedStreamReaderOrStringReader(csvStream, encoding ?? Encoding.UTF8);
return ReadCsvLinesIntoDataFrame(wrappedStreamReaderOrStringReader, separator, header, columnNames, dataTypes, numberOfRowsToRead, guessRows, addIndexColumn);
return ReadCsvLinesIntoDataFrame(wrappedStreamReaderOrStringReader, separator, header, columnNames, dataTypes, numberOfRowsToRead, guessRows, addIndexColumn, renameDuplicatedColumns);
}

/// <summary>
Expand Down
40 changes: 40 additions & 0 deletions test/Microsoft.Data.Analysis.Tests/DataFrame.IOTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -154,6 +154,46 @@ void ReducedRowsTest(DataFrame reducedRows)
ReducedRowsTest(csvDf);
}

[Fact]
public void TestReadCsvWithHeaderAndDuplicatedColumns_WithoutRenaming()
{

string data = @$"vendor_id,rate_code,passenger_count,trip_time_in_secs,trip_distance,payment_type,payment_type,fare_amount
CMT,1,1,1271,3.8,CRD,CRD,17.5
CMT,1,1,474,1.5,CRD,CRD,8
CMT,1,1,637,1.4,CRD,CRD,8.5
CMT,1,1,181,0.6,CSH,CSH,4.5";

Assert.Throws<System.ArgumentException>(() => DataFrame.LoadCsv(GetStream(data)));
}

[Fact]
public void TestReadCsvWithHeaderAndDuplicatedColumns_WithDuplicateColumnRenaming()
{

string data = @$"vendor_id,rate_code,passenger_count,trip_time_in_secs,trip_distance,payment_type,payment_type,payment_type,fare_amount
CMT,1,1,1271,3.8,CRD,CRD_1,Test,17.5
CMT,1,1,474,1.5,CRD,CRD,Test,8
CMT,1,1,637,1.4,CRD,CRD,Test,8.5
CMT,1,1,181,0.6,CSH,CSH,Test,4.5";

DataFrame df = DataFrame.LoadCsv(GetStream(data), renameDuplicatedColumns: true);

Assert.Equal(4, df.Rows.Count);
Assert.Equal(9, df.Columns.Count);
Assert.Equal("CMT", df.Columns["vendor_id"][3]);

Assert.Equal("payment_type", df.Columns[5].Name);
Assert.Equal("payment_type.1", df.Columns[6].Name);
Assert.Equal("payment_type.2", df.Columns[7].Name);

Assert.Equal("CRD", df.Columns["payment_type"][0]);
Assert.Equal("CRD_1", df.Columns["payment_type.1"][0]);
Assert.Equal("Test", df.Columns["payment_type.2"][0]);

VerifyColumnTypes(df);
}

[Fact]
public void TestReadCsvSplitAcrossMultipleLines()
{
Expand Down