import from CSV into Ruby array, with 1st field as hash key, then lookup a field's value given header row

Question

Maybe somebody can help me.

Starting with a CSV file like so:

Ticker,\"Price\",\"Market Cap\"
ZUMZ,30.00,933.90
XTEX,16.02,811.57
AAC,9.83,80.02
         


        

Answer 1

While this isn't a 100% native Ruby solution to the original question, should others stumble here and wonder what awk call I wound up using for now, here it is:

$dividend_yield = IO.readlines("|awk -F, '$1==\"#{$stock}\" {print $9}' datafile.csv")[0].to_f

where $stock is the variable I had previously assigned to a company's ticker symbol (the wannabe key field). Conveniently survives problems by returning 0.0 if: ticker or file or field #9 not found/empty, or if value cannot be typecasted to a float. So any trailing '%' in my case gets nicely truncated.

Note that at this point one could easily add more filters within awk to have IO.readlines return a 1-dim array of output lines from the smaller resulting CSV, eg.

 awk -F, '$9 >= 2.01  &&  $2 > 99.99  {print $0}' datafile.csv 

outputs in bash which lines have a DivYld (col 9) over 2.01 and price (col 2) over 99.99. (Unfortunately I'm not using the header row to to determine field numbers, which is where I was ultimately hoping for some searchable associative Ruby array.)