Jan's Blog

Author: jvdl

One-time-pad encryption with R and basic JavaScript

One-time-pad encryption offers unbreakable* security if you can guarantee truly random number generation and security of the generated pad. Implementing it from the perspective of a cryptographic layman is a fun way to learn more about it and could add an extra layer of security to your most sensitive communications. I started off by trying […]

Searching for a string in an entire SAS library

For the most part, experienced SAS programmers know where to look for the source data they need. In the pharmaceutical industry, we are familiar with CDISC standards and data structures. However, should the data standard be unfamiliar or the source datasets include new or unusual parameters, it may be prudent to have SAS look through […]

NONMEM ADDL Calculation and Compression in SAS

ADDL represents the number of additional doses that are copies of the current row, with the time since first dose (RTFD) increased at the regular dosing interval (II). This allows for the compression of dose records in the NONMEM dataset. To put it more eloquently: The NONMEM data item ADDL on a dose record expresses […]

SAS and the Forward Re-scan Rule

The “Forward Re-scan Rule” (FRR) is used by SAS to resolve macro variables over several passes. This is especially useful when having one macro variable point to another macro variable, or when trying to resolve numbered macro variables. The SAS Advanced Prep Guide summarises the FRR as follows: Example: numbered list of macro variables To […]

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