Improving the phone book application
It is time to update the phone book application. The new version of the phone book utility has the following improvements:
- Support for the
insert
anddelete
commands - Ability to read data from a file and write it before it exits
- Each entry has a last visited field that is updated
- Has a database index that is implemented using a Go map
- Uses regular expressions to verify the phone numbers read
Working with CSV files
Most of the time you do not want to lose your data or have to begin without any data every time you execute your application. There exist many techniques for doing so—the easiest one is by saving your data locally. A very easy to work with format is CSV, which is what is explained here and used in the phone book application later on. The good thing is that Go provides a dedicated package for working with CSV data named encoding/csv
(https://golang.org/pkg/encoding/csv/). For the presented...