08-phone

Gophercises - 8 - Phone Number Normalizer

Problem

• https://github.com/gophercises/phone
• https://gophercises.com/exercises/phone

Solution

• main.go.

  $ go run main.go --help
    -db string
          database file (default "phones.db")
    -ph string
          file with original phone numbers (default "phones.txt")
  

You need to go get:

• https://github.com/jmoiron/sqlx
• https://github.com/mattn/go-sqlite3

go-sqlite3 needs cgo. I had to install MinGW-w64 on Windows:

• https://sourceforge.net/projects/mingw-w64/
• Change the architecture to x86_64 if on a 64-bit system and keep everything else.
• After installation, add the bin directory to PATH.
  • E.g. C:\Program Files\mingw-w64\x86_64-8.1.0-posix-seh-rt_v6-rev0\mingw64\bin

Lessons Learned

jmoiron/sqlx

Troubleshooting:

• Problem: panic: sql: unknown driver "sqlite3" (forgotten import?)

• Solution: import _ "github.com/mattn/go-sqlite3"

• Problem:

  # github.com/mattn/go-sqlite3
  exec: "gcc": executable file not found in %PATH%
  

• Solution: Install https://sourceforge.net/projects/mingw-w64/ (see above).

Good examples:

• https://jmoiron.github.io/sqlx/

• https://github.com/joncrlsn/go-examples/blob/master/sqlx-sqlite.go

• Problem: "missing destination name" error when using Queryx and StructScan.

• Solutions:

  • Struct fields must be exported.
  • Map the table columns to struct fields with db:"table-column".

Usage

$ go run main.go
Creating phone_numbers.
Adding phone numbers to the table.
Reading from phone_numbers.
Creating unique_numbers.
Adding unique phone numbers to unique_numbers.
Reading unique phone numbers from unique_numbers.
1234567891
1234567892
1234567893
1234567894
1234567890