How can I skip the index out of range error?

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I am still wondering if there is a better way to do this.for example.
I want to get all the columns of the matrix a:
a := [][]string{
{“a”, “b”, “c”, “d”},
{“e”, “f”, “g”, “h”},
{“i”, “j”},
}

Here is my code:
https://play.golang.org/p/Z3owzthPnZ
I think it is very clumsy.If I can skip the index out of range error,it can save a lot of time