Signature Description Parameters
bool
read(const char *file_name, io_format iof = io_format::csv);
It inputs the contents of a text file into itself (i.e. DataFrame). Currently two formats (i.e. csv, json) are supported specified by the iof parameter.
The csv file format must be:
INDEX::
<Column1 name>:<Number of data points>:<Column1 type>:<Comma delimited list of values>
<Column2 name>:<Number of data points>:<Column2 type>:<Comma delimited list of values>
.
.
.
All empty lines or lines starting with # will be skipped.

The JSON file format looks like this:
{
    "INDEX":{"N":3,"T":"ulong","D":[123450,123451,123452]},
    "col_3":{"N":3,"T":"double","D":[15.2,16.34,17.764]},
    "col_4":{"N":3,"T":"int","D":[22,23,24]},
    "col_str":{"N":3,"T":"string","D":["11","22","33"]},
    "col_2":{"N":3,"T":"double","D":[8,9.001,10]},
    "col_1":{"N":3,"T":"double","D":[1,2,3.456]}
}
Please note DataFrame json does not follow json spec 100%. In json, there is no particular order in dictionary fields. But in DataFrame json:
  1. Column “INDEX” must be the first column
  2. Fields in column dictionaries must be in N, T, D order
file_name: Complete path to the file
iof: Specifies the I/O format. The default is CSV
std::future<bool>
read_async(const char *file_name, io_format iof = io_format::csv);
Same as read() above, but executed asynchronously file_name: Complete path to the file
iof: Specifies the I/O format. The default is CSV