Runtime Error: index out range

[TekTimmy]

While comparing 2 CSV files I get the following runtime error:

panic: runtime error: index out of range [2] with length 0

goroutine 1 [running]:
github.com/aswinkarthik/csvdiff/pkg/digest.Positions.String(0xc0000b2380, 0xc, 0x10, 0x0, 0x0, 0x0, 0xc00000003b, 0xc004774b60, 0xd6)
        /home/travis/gopath/src/github.com/aswinkarthik/csvdiff/pkg/digest/positions.go:35 +0x332
github.com/aswinkarthik/csvdiff/cmd.(*Formatter).json(0xc00010bac0, 0xb1a638, 0x0, 0x0, 0xc005bc6000, 0x78fe, 0x8f55, 0xb1a638, 0x0, 0x0, ...)
        /home/travis/gopath/src/github.com/aswinkarthik/csvdiff/cmd/formatter.go:130 +0x4de
github.com/aswinkarthik/csvdiff/cmd.(*Formatter).Format(0xc00010bac0, 0xb1a638, 0x0, 0x0, 0xc005bc6000, 0x78fe, 0x8f55, 0xb1a638, 0x0, 0x0, ...)
        /home/travis/gopath/src/github.com/aswinkarthik/csvdiff/cmd/formatter.go:45 +0x1a5
github.com/aswinkarthik/csvdiff/cmd.runContext(0xc000104000, 0x884060, 0xc000010018, 0x884060, 0xc000010020, 0x0, 0x0)
        /home/travis/gopath/src/github.com/aswinkarthik/csvdiff/cmd/root.go:108 +0x4c5
github.com/aswinkarthik/csvdiff/cmd.glob..func2(0xaf89c0, 0xc0000b50e0, 0x2, 0xa, 0x0, 0x0)
        /home/travis/gopath/src/github.com/aswinkarthik/csvdiff/cmd/root.go:87 +0x283
github.com/spf13/cobra.(*Command).execute(0xaf89c0, 0xc0000120c0, 0xa, 0xa, 0xaf89c0, 0xc0000120c0)
        /home/travis/gopath/pkg/mod/github.com/spf13/cobra@v0.0.5/command.go:826 +0x460
github.com/spf13/cobra.(*Command).ExecuteC(0xaf89c0, 0xc00006eda0, 0xc00006bf20, 0x43cb8a)
        /home/travis/gopath/pkg/mod/github.com/spf13/cobra@v0.0.5/command.go:914 +0x2fb
github.com/spf13/cobra.(*Command).Execute(...)
        /home/travis/gopath/pkg/mod/github.com/spf13/cobra@v0.0.5/command.go:864
github.com/aswinkarthik/csvdiff/cmd.Execute()
        /home/travis/gopath/src/github.com/aswinkarthik/csvdiff/cmd/root.go:115 +0x76
main.main()
        /home/travis/gopath/src/github.com/aswinkarthik/csvdiff/main.go:29 +0x59

When I change the primary key column the problem does not occur anymore.
I'm sorry for not providing the CSVs but they contain sensitive data and are 24MB of size.