Textreader csv file

But naming our properties in Japanese is madness, so what can we do? The ClassMap comes to the rescue. Essentially, we subclass ClassMap and use it to tell CsvHelper which column should be mapped to which property. Then all we need to do is register this mapping class with CsvHelper before calling csv. It is also possible to skip some columns in the CSV file. The solution above works fine if columns in our CSV file all have unique names.

But if there are multiple columns with the same name then only the first column is mapped. Mapping by index is very similar to mapping by name, the only difference is what we chain to the Map function. Moreover, we can mix mapping by name and mapping by index. We just need to make sure that all properties are mapped one way or another. This is because when a mapping class exists, implicit auto mapping is disabled. In this case, we also need to set the HasHeaderRecord flag in config to false.

Maybe you have realized that the Age property in our Person class is an Integer , but a CSV file only contains text data. CsvHelper can convert data from string into standard. You can find the list of converters that CsvHelper supports in this link. Instructs reader to perform no special processing of quote characters. The csv module defines the following exception:. To make it easier to specify the format of input and output records, specific formatting parameters are grouped together into dialects.

A dialect is a subclass of the Dialect class having a set of specific methods and a single validate method. When creating reader or writer objects, the programmer can specify a string or a subclass of the Dialect class as the dialect parameter.

In addition to, or instead of, the dialect parameter, the programmer can also specify individual formatting parameters, which have the same names as the attributes defined below for the Dialect class. A one-character string used to separate fields. It defaults to ','. Controls how instances of quotechar appearing inside a field should themselves be quoted. When True , the character is doubled. When False , the escapechar is used as a prefix to the quotechar.

It defaults to True. On output, if doublequote is False and no escapechar is set, Error is raised if a quotechar is found in a field. On reading, the escapechar removes any special meaning from the following character. It defaults to None , which disables escaping. The string used to terminate lines produced by the writer. This behavior may change in the future. A one-character string used to quote fields containing special characters, such as the delimiter or quotechar , or which contain new-line characters.

It defaults to '"'. Controls when quotes should be generated by the writer and recognised by the reader. When True , whitespace immediately following the delimiter is ignored. The default is False. Reader objects DictReader instances and objects returned by the reader function have the following public methods:. Usually you should call this as next reader. The number of lines read from the source iterator.

This is not the same as the number of records returned, as records can span multiple lines. If not passed as a parameter when creating the object, this attribute is initialized upon first access or when the first record is read from the file. Writer objects DictWriter instances and objects returned by the writer function have the following public methods. We read the fields of the record with TryGetField.

In the example, we define the User class and read the records of the users. The GetRecords returns the IEnumerable of the given type. In the following example, we are going to have a CSV file with semicolon separators and a comment. In order to parse such a different "CSV" file, we need to configure the parser.

We tell the reader that there is no header and that the comment character is. TextReader class is found under System. IO namespace. It is an abstract base class of StreamReader and StringReader which are used to read characters from stream and string respectively. We cannot create an object of TextReader because it is an abstract class. TextReader is not threaded safe by default.

Class deriving TextReader class needs to minimally implement Peek and Read methods in order to make a useful instance of TextReader. In order to work with TextReader, it is necessary to import System. IO namespace in our code.

The OpenText method takes the location of the file as input and then it opens an existing UTF-8 encoded text file at the same location for reading. The File. OpenText method returns an object of the StreamReader class which is the derived class of TextReader and thus helps in creating a useful instance of TextReader class in the code.