Commands

Note: <arg> is a required argument, [arg] is optional

• read <filename: str>
  • Read a csv file and create a stream of data. It will attempt to parse each value if possible.
• write <filename: str>
  • Write the stream of data to file as csv
• drop head <count: int>
  • Drop count rows from the beginning (aka top of table)
• print [header: str]
  • Print out the current data stream. If header is specified, print the string before the data.
• columns <order: tuple[int]>
  • Reorder or drop columns. Columns are 1-indexed, so for example, if we have 3 columns and specify (3,2,1), we reverse the order of columns.
• parse <types: tuple[ident]>
  • Parse strings to data types like integers, decimal numbers, or dates. Valid elements of config are: int for integers, float for decimal numbers, and date for dates.
• classify <column: int> <rules: tuple[rule]>
  • Classify the elements in specified column according to a given set of rules. If more than one rule apply, the first matching rule is used. The produced classification is added as a column to the right of the table (i.e. appended to each row). If no rule matches, it will use
• filter <column: int> <match pattern>
  • Only keeps rows where the element in the specified column matches the pattern
• sum <column: int>
  • Sum all the entries in the given columns. Strings will be appended, and if strings are numbers are encountered, the numbers will be turned into strings.

Command Line Arguments

Command line arguments can be used anywhere where an argument is required. Simply put $n, where n is the nth command line argument. The 0th argument is always the name of the script.

For example: If test.fluss is

read $1 >> drop head 2 >> print >> sum 3 >> print

then

cargo run -- test.fluss '"data.csv"'

will substitute the $1 with "data.csv". Note: Command line arguments are parsed as arguments just like arguments in the script file. Bash removes the outer quotes and so '"data.csv"' means that the script parses "data.csv", which it recognizes as a string. Without the extra quotes, it would try to interpret it as an command option like head instead of an arbitrary string.

Syntax

Match Rules

Rules follow the syntax: <match pattern> => <value>

• Value can be a string, int, or float
• If nothing matches, the default value of the empty string is used.

Strings

• String matching is case-insensitive
• "foo" => "This is foo"
  • Matches "foo" exactly
• "foo*" => "This is foo"
  • Matches strings starting with "foo"
• "*foo" => "This is foo"
  • Matches strings ending with "foo"
• "*foo*" => "This is foo"
  • Matches strings containing "foo"