[Gretl-devel] RFC: strscrape function

I'm wondering whether people would consider this function (which I'm calling "strscrape" for now) worth having: it takes a string argument and returns a row vector containing any numerical values encountered in the string (or an empty matrix if none are found). There's a test version in git but it's not documented; I'm not committed to keeping it if doesn't attract much support. Unlike using sscanf() to retrieve a matrix, the idea with this function is that the numbers may be embedded in arbitrary text. Numbers are identified as starting with either a minus sign (followed directly by a digit) or a digit, and their length in characters is decided by the C function strtod (so scientific notation is acceptable). As the function stands, the decimal character is unconditionally '.'. One use for such a function would be "remedial" -- getting values back from a gretl command when there's no relevant accessor. Here's a semi-general illustration: <hansl> function matrix scrapevals (const string cmd, const list L[null]) string fname = sprintf("%s/_tmp.txt", $dotdir) set force_decpoint on outfile @fname --write --quiet @cmd outfile --close string s = readfile(fname) remove(fname) return strscrape(s) end function open data4-10 list L = ENROLL CATHOL matrix m = scrapevals("corr L --kendall", L) print m </hansl> However, it could also be useful for processing text other than gretl's own output. Here's a generic example: <hansl> string s="Here is some text 1.5e-4with embedded 12345 numbers \ stuck int0 1t." matrix vals = strscrape(s) print vals </hansl> which gives vals (1 x 4) 0.00015000 12345. 0.0000 1.0000 Allin