Compactly display the structure of an arbitrary R object

September 21, 2012

(This article was first published on is.R(), and kindly contributed to R-bloggers)

As you advance in your R use past “canned” functions and packages made by others, you may want to take information from one R object for use in another.

For example, you may want to estimate a linear model, then use the results of that estimation to:

  • Use coefficient values and the variance-covariance matrix to simulate from the model,
  • Visualize model diagnostics, including the distribution of residuals,
  • Feed into another model as prior information,
  • Etc.

str() is a function that allows you to examine any R object, in order to “see what’s inside,” so to speak. In the case of a linear model produced by lm(), the model object (as well as the model summary object) is a list that contains a lot of information, permitting the assessment of model fit, diagnostic plotting, prediction, etc.

The following Gist is a rather unimaginative introduction to the use of str(), but as is often the case, simply knowing of its existence is of great use.

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