Use this function to find a value in an external file.
Parameters: filename, key value of row, column number, separator(s), allow empty columns
Separators and allowing empty columns are optional parameters. The default separators are space and tab. The default for allowing empty columns is FALSE.
Where the format for reading files is:
fvf("filename", "key_value_of_row", column_number, "separator(s)", FALSE)
The path for the file can be included in the filename parameter.
Template Editor supports several separators, so " ,\t" would make all the space, comma, tab and newline characters separators.
The function retrieves the value P20(200x1200) from column 3 of the row identified by the string "2" in the file "hollowcore_slab_dim.dat."
Below are several hypothetical examples that illustrate how the syntax in the fvf formula produces different results, including the use of a fifth parameter in the formula to produce empty columns.
This example specifies an input file called "sample.dat", with the line:
A; B;; C; D
In this case, the formula
will return an empty string: ""
As each separator in the above example is considered meaningful, the third column is an empty column between the first ';' and the first ' ' separators. So the column values in this case are:
1: "A"
2: " B"
3: ""
4: " C"
5: " D"
and
will return: "C"
A subsequent example would be when multiple separators are used in the input file, i.e. a mix of spaces and commas.
A, B, C, D
In this case, the formula:
will return: "B"
and
will return an empty string: ""
and
will output: "C"
and finally
will output: "D"
That is, when the last parameter is FALSE, consecutive separators are interpreted as one separator.
TRUE = allow empty columns, thus consecutive separators are treated as unique separators.
FALSE = do not allow empty columns, thus consecutive separators are treated as one separator.
For more information related to the support for this function, consult How to read data from a text file in Custom Components.