Editing Rope (data structure) (section)

=== Insert ===
: ''Definition:'' <code>Insert(i, S’)</code>: insert the string ''S’'' beginning at position ''i'' in the string ''s'', to form a new string {{math|''C''<sub>1</sub>, ..., ''C<sub>i</sub>'', ''S''', ''C''<sub>''i'' + 1</sub>, ..., ''C<sub>m</sub>''}}.
: ''Time complexity:'' {{tmath|O(\log N)}}.

This operation can be done by a <code>Split()</code> and two <code>Concat()</code> operations. The cost is the sum of the three.
<syntaxhighlight lang="java">
public Rope insert(int idx, CharSequence sequence) {
    if (idx == 0) {
        return prepend(sequence);
    }
    if (idx == length()) {
        return append(sequence);
    }
    val lhs = base.split(idx);
    return new Rope(Ropes.concat(lhs.fst.append(sequence), lhs.snd));
}
</syntaxhighlight>