previous post<\/a>, we saw how to run Pig Latin instructions as a script. But there is one problem with that; we hard coded the Input and the Output location and it is not ideal. In this lesson we will see how we can pass parameters to the script.<\/p>\nParameter Placeholders<\/h2>\n
Take a look at the below sample. ‘$input’ is a parameter which defines the input location and ‘$output’ is a parameter which defines the output location.<\/p>\n
prices = LOAD '$input' USING PigStorage(',') as (exchange:chararray, symbol:chararray, date:datetime, open:float, high:float, low:float, close:float,volume:int, adj_close:float);<\/pre>\nSTORE top10 INTO '$output' USING PigStorage(',');<\/pre>\nPassing Parameters<\/h2>\n
Now we know how to set the parameters, let’s see how to pass parameters from the command line. Use -param<\/span>\u00a0\u00a0and the parameter name to set and pass the value for the paramaters. In the below sample, at run time the value of the $input<\/span>\u00a0\u00a0in the script will be substituted as\u00a0\/user\/hirw\/input\/stocks<\/span><\/p>\npig -param input=\/user\/hirw\/input\/stocks -param output=output\/pig\/avg-volume-params \/hirw-workshop\/pig\/scripts\/average-volume-parameters.pig<\/pre>\n\u00a0See It In Action<\/h2>\n