This will read one row at a time & use a lot less memory. If you want to process big CSV files (> 10MB) you may want to use the CSV.foreach(file_name) method with a block.
#Ruby on rails file upload example how to#
You've learned how to read & write CSV files in Ruby! You've also learned about converters & alternative Ruby gems to process your CSV data. The Ruby CSV library implements something called converters.Ī converter will automatically transform values for you.ĬSV.parse("1,2,3,4,5", converters: :numeric)īut you can also create your own custom converters.ĬSV::Converters = ->(value) ] You can get them by calling to_i on each string… You may have noticed that we got our id column as an array of strings. This is going to be more memory-efficient because no copy of the table is created. If you want to make changes to the original table then you can use the by_col! & by_row! methods. There is, AFAIK, no possibility to treat fileupload as typical field ( See File upload won't work in. However, I cannot find any usage for this case, as those tags are used to create/edit some model, by mass assigning. I found filefield :file helper, that can be used with formfor(somemodel). These two methods return a copy of the table. I came across file uploading problem in Rails.
Here 0 is the first column, 1 is the second column. Here 0 is the first row, id & name are the column names.īy changing the table mode ( row by default) you can look at the data from different angles. Given one of these tables, you can get the data you need from any row. Tables allow you to work with the data by row or column, manipulate the data, and even convert the results back to CSV.” “A CSV::Table is a two-dimensional data structure for representing CSV documents. Now instead of a multi-dimensional array you get a CSV Table object. Table = CSV.parse(File.read("cats.csv"), headers: true) If your file has headers you can tell the CSV parser to use them. You can use array indices like data to work with this data. You get a two-dimensional array where every entry is one row in the table. Ruby CSV ParsingĬSV.parse("1,chocolate\n2,bacon\n3,apple") Now you’re going to learn how to use the Ruby CSV library to read & write CSV files. You can export your Gmail contacts as a CSV file, and you can also import them using the same format. It’s used for exporting & importing data. It involves the use of ActiveStorage, which is a built-in solution introduced by rails 5.2 that offers a simplified way of handling file uploads to either your server or cloud services like Azure. It’s a common data format which consist of rows with values separated by commas.