Allow empty items

src/FileParser/Implementations/ParsedFile.cs

@@ -31,8 +31,9 @@ public ParsedFile(Queue<IParsedLine> parsedFile)
         /// </summary>
         /// <param name="path">FilePath</param>
         /// <param name="existingSeparator">Word separator (space by default)</param>
-        public ParsedFile(string path, char[] existingSeparator)
-            : this(path, new string(existingSeparator))
+        /// <param name="ignoreEmptyItems"></param>
+        public ParsedFile(string path, char[] existingSeparator, bool ignoreEmptyItems = true)
+            : this(path, new string(existingSeparator), ignoreEmptyItems)
         {
         }
 
@@ -41,9 +42,10 @@ public ParsedFile(string path, char[] existingSeparator)
         /// </summary>
         /// <param name="path">FilePath</param>
         /// <param name="existingSeparator">Word separator (space by default)</param>
-        public ParsedFile(string path, string? existingSeparator = null)
+        /// <param name="ignoreEmptyItems"></param>
+        public ParsedFile(string path, string? existingSeparator = null, bool ignoreEmptyItems = true)
 #pragma warning disable CS0618 // Type or member is obsolete - will keep it as private
-            : base(ParseFile(path, existingSeparator))
+            : base(ParseFile(path, existingSeparator, ignoreEmptyItems))
 #pragma warning restore CS0618 // Type or member is obsolete
         {
         }
@@ -207,14 +209,15 @@ public static List<List<T>> ReadAllGroupsOfLines<T>(string path)
         /// </summary>
         /// <param name="path"></param>
         /// <param name="existingSeparator">Word separator</param>
+        /// <param name="ignoreEmptyItems"></param>
         /// <exception cref="FileNotFoundException"></exception>
         /// <exception cref="DirectoryNotFoundException"></exception>
         /// <exception cref="IOException"></exception>
         /// <exception cref="ArgumentException"></exception>
         /// <exception cref="ArgumentNullException"></exception>
         /// <returns></returns>
         [Obsolete("This method exposes internal functionality and was made public accidentally. It will be removed in next major release, please used ParsedFile constructor instead.")]
-        public static Queue<IParsedLine> ParseFile(string path, string? existingSeparator = null)
+        public static Queue<IParsedLine> ParseFile(string path, string? existingSeparator = null, bool ignoreEmptyItems = true)
         {
             Queue<IParsedLine> parsedFile = new();
 
@@ -233,7 +236,7 @@ public static Queue<IParsedLine> ParseFile(string path, string? existingSeparato
                         }
                         // end TODO
 
-                        IParsedLine parsedLine = new ParsedLine(ProcessLine(original_line, existingSeparator));
+                        IParsedLine parsedLine = new ParsedLine(ProcessLine(original_line, existingSeparator, ignoreEmptyItems));
                         parsedFile.Enqueue(parsedLine);
                     }
                 }
@@ -248,13 +251,16 @@ public static Queue<IParsedLine> ParseFile(string path, string? existingSeparato
             }
         }
 
-        private static ICollection<string> ProcessLine(string original_line, string? separator)
+        private static ICollection<string> ProcessLine(string original_line, string? separator, bool ignoreEmptyItems)
         {
             List<string> wordsInLine = original_line
                 .Split(separator?.ToCharArray())
                 .Select(str => str.Trim()).ToList();
 
-            wordsInLine.RemoveAll(string.IsNullOrWhiteSpace);   // Probably not needed, but just in case
+            if (ignoreEmptyItems)
+            {
+                wordsInLine.RemoveAll(string.IsNullOrWhiteSpace);
+            }
 
             return wordsInLine;
         }

src/FileParser/Utils/StringConverter.cs

@@ -14,6 +14,11 @@ internal static class StringConverter
         /// <returns></returns>
         public static T Convert<T>(string str, TypeConverter? typeConverter = null)
         {
+            if (str.Length == 0)
+            {
+                return default!;
+            }
+
             return default(T) switch
             {
                 short => (T)(object)short.Parse(str),

tests/FileParser.Test/ParsedFileTest/ExtractTests.cs

@@ -72,5 +72,118 @@ public void ExtractChar()
 
             Assert.Equal(line1 + '\\' + line2 + '\\', parsedFile.ToString());
         }
+
+        [Fact]
+        public void MultipleCharWordSeparator()
+        {
+            const string fileName = "MultipleCharWordSeparator.txt";
+            const string line1 = "   FirstName|| LastName  ||Age||EyeColor ";
+            const string line2 = "           John|| Doe||66 ||  Brown";
+
+            var expectedFirstLine = new[] { "FirstName", "LastName", "Age", "EyeColor" };
+            var expectedSecondLine = new[] { "John", "Doe", "66", "Brown" };
+
+            using (StreamWriter writer = new(fileName))
+            {
+                writer.WriteLine(line1);
+                writer.WriteLine(line2);
+            }
+
+            IParsedFile file = new ParsedFile(fileName, "||");
+
+            int index = 0;
+            var line = file.NextLine();
+            while (!line.Empty)
+            {
+                var item = line.NextElement<string>();
+                Assert.Equal(expectedFirstLine[index++], item);
+            }
+
+            line = file.NextLine();
+            Assert.Equal(expectedSecondLine, line.ToList<string>());
+
+            Assert.True(file.Empty);
+        }
+
+        [Fact]
+        public void ParseCsvFileIntoStrings()
+        {
+            const string fileName = "ParseCsvFileIntoStrings.txt";
+            const string line1 = "FirstName,LastName,Age,EyeColor";
+            const string line2 = "John,Doe,66,Brown";
+            const string line3 = "Cthulhu,,1000,Black";
+            const string line4 = "Bugs,Bunny,33,White";
+
+            using (StreamWriter writer = new(fileName))
+            {
+                writer.WriteLine(line1);
+                writer.WriteLine(line2);
+                writer.WriteLine(line3);
+                writer.WriteLine(line4);
+            }
+
+            IParsedFile file = new ParsedFile(fileName, ",", ignoreEmptyItems: false);
+
+            var headerLine = file.NextLine();
+            var buckets = new List<List<string>>(headerLine.ToList<string>().Select(header => new List<string>(1000) { ModifyString(header) }));
+
+            while (!file.Empty)
+            {
+                var line = file.NextLine().ToList<string>();
+                for (int index = 0; index < line.Count; ++index)
+                {
+                    buckets[index].Add(ModifyString(line[index]));
+                }
+            }
+
+            static string ModifyString(string str) => str.ToLowerInvariant();
+
+            Assert.Equal(new[] { "firstname", "john", "cthulhu", "bugs" }, buckets[0]);
+            Assert.Equal(new[] { "lastname", "doe", "", "bunny" }, buckets[1]);
+            Assert.Equal(new[] { "age", "66", "1000", "33" }, buckets[2]);
+            Assert.Equal(new[] { "eyecolor", "brown", "black", "white" }, buckets[3]);
+        }
+
+        [Fact]
+        public void ParseCsvFile()
+        {
+            const string fileName = "ParseCsvFile.txt";
+            const string line1 = "Name,Age,Score";
+            const string line2 = "Abraham,10,9.05";
+            const string line3 = "Babilon,,64.05";
+            const string line4 = "Croc,99,";
+
+            using (StreamWriter writer = new(fileName))
+            {
+                writer.WriteLine(line1);
+                writer.WriteLine(line2);
+                writer.WriteLine(line3);
+                writer.WriteLine(line4);
+            }
+
+            IParsedFile file = new ParsedFile(fileName, ",", ignoreEmptyItems: false);
+
+            file.NextLine();
+
+            var line = file.NextLine();
+
+            Assert.Equal("Abraham", line.NextElement<string>());
+            Assert.Equal(10, line.NextElement<int>());
+            Assert.Equal(9.05, line.NextElement<double>());
+
+            line = file.NextLine();
+
+            Assert.Equal("Babilon", line.NextElement<string>());
+            Assert.Equal(default, line.NextElement<int>());
+            Assert.Equal(64.05, line.NextElement<double>());
+
+            line = file.NextLine();
+
+            Assert.Equal("Croc", line.NextElement<string>());
+            Assert.Equal(99, line.NextElement<int>());
+            Assert.Equal(default, line.NextElement<double>());
+
+            Assert.True(file.Empty);
+        }
     }
 }