The "splitstackshape" package for R

A while ago, a friend of ours presented me with a data problem. Her questionnaire had some questions where the respondent could provide multiple responses. You know, the "Check as many as apply" type of questions. One way that this data is commonly stored is to put a comma separated value into a single cell in a spreadsheet. In fact, if you use something like Google Forms to collect your data and have questions that use check-boxes, that's how your data will finally be stored in a Google Spreadsheet.