  Mean residual lifetime is an important measure utilized in various fields,
including pharmaceutical companies, manufacturing companies, and insurance
companies for survival analysis. However, the computation of mean residual
lifetime can be laborious and challenging. To address this issue, the R package
reslife has been developed, which enables efficient calculation of mean
residual lifetime based on closed-form solution in a user-friendly manner.
reslife offers the capability to utilize either the results of a flexsurv
regression or user-provided parameters to compute mean residual lifetime.
Furthermore, there are options to return median and percentile residual
lifetime. If the user chooses to use the outputs of a flexsurv regression,
there is an option to input a data frame with unobserved data. In this article,
we present reslife, explain its underlying mathematical principles, illustrate
its functioning, and provide examples on how to utilize the package. The aim is
to facilitate the use of mean residual lifetime, making it more accessible and
efficient for practitioners in various disciplines, particularly those involved
in survival analysis within the pharmaceutical industry. This package has been
approved and available on CRAN:
https://cran.r-project.org/web/packages/reslife/index.html
