how to split long lines for fmt.sprintf

Question

I have a very long line in fmt.Sprintf. How do I split it in the code? I don't want to put everything in a single line so the code looks ugly.

fmt.Sprintf("a:%s, b:%s  ...... this goes really long")

Answer 1

Use string concatenation to construct a single string value on multiple lines:

 fmt.Sprintf("a:%s, b:%s " +
    " ...... this goes really long",
    s1, s2)

The long string in this example is built at compile time because the string concatenation is a constant expression.

You can split the string at contained newlines using a raw string literal:

     fmt.Sprintf(`this text is on the first line
and this text is on the second line,
and third`)

Answer 2

You can also use raw string literals inside backticks, like this:

columns := "id, name"
table := "users"
query := fmt.Sprintf(`
    SELECT %s
    FROM %s
  `, columns, table)
fmt.Println(query)

There are a few caveats to this approach:

1. Raw strings don't parse escape sequences
2. All the whitespace will be preserved, so there will be a newline and then several tabs before the FROM clause in this query.

These problems can be a challenge for some, and the whitespace will produce some ugly resulting strings. However, I prefer this approach as it allows you to copy and paste long, complex SQL queries outside of your code and into other contexts, like sql worksheets for testing.