 class="op">&lt;-</span> <span class="fu"><a href="https://rdrr.io/pkg/survival/man/coxph.html" class="external-link">coxph</a></span><span class="op">(</span><span class="fu"><a href="https://rdrr.io/pkg/survival/man/Surv.html" class="external-link">Surv</a></span><span class="op">(</span><span class="va">time</span>, <span class="va">event</span><span class="op">)</span> <span class="op">~</span> <span class="va">x1</span> <span class="op">+</span> <span class="va">x2</span> <span class="op">+</span> <spa