Angara.Table

Save and Load

The Table type exposes static functions Save and Load to save and load a table in the delimited text format (CSV) in accordance with RFC 4180 but with extended set of delimiters: comma, tab, semicolon and space.

The Table.Save function saves a table to a file or using given TextWriter:

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Table.Save(table, "table.csv")

The table.csv contains the following text:

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x,sin(x)
0,0
0.1,0.099833416646828155
0.2,0.19866933079506122
0.3,0.29552020666133955
...

To load a table from a delimited text file, such as CSV file, or using given TextReader, you can call Table.Load function:

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let table = Table.Load "table.csv"

The overloaded functions Load and Save allow to provide custom settings, such as specific delimiter, header, support of null strings, and predefined columns count and types.

Column Type Inference

Table.Load infers columns types from the text. Note that by default numeric values are always read as float and never as int to avoid ambiguity. If you need an integer column, you can provide custom settings to the Load function with specific ColumnTypes function.

Typed Table

To load a typed table, use the following snippet:

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type SinX = { x: float; ``sin(x)``: float }

let tableSinX : Table<SinX> = 
    (Table.Load "table.csv").ToRows<SinX>()
    |> Table.OfRows

Read more about typed tables in Table as Collection of Rows.

Null and Empty Strings

By default, Save fails if the table contains null strings to avoid ambiguity with empty strings. If the custom WriteSettings provided to the Save method and its AllowNullStrings is true, it saves a null string as an empty string and an empty string as two double quotes (""). The default Load both empty string and two double quotes reads as an empty string; if custom ReadSettings has InferNullStrings set to true, double quotes ("") are considered as empty string and an empty string is considered as null.

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