PR Details

Add rows.IterateColumns(iterateFunc), iterate it with a callback function instead create a huge []string.And that will enhance memory performance

Related Issue

close #2191

Example:

err := rows.IterateColumns(func(index int, cell string) error {
    fmt.Printf("column %d: %s\n", index, cell)
    return nil
})

How Has This Been Tested

go test

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• [] My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.