我想通过knitr在我的.Rnw文件中joinrglgraphics。 这是我的MWE: \documentclass{article} << label = setup, include = FALSE>>= opts_chunk$set(fig.path = 'figure/', cache = FALSE, dev = "pdf", fig.align = 'center', fig.show = 'hold', fig.width = 3, fig.height = 3, echo = TRUE, warning = FALSE, message = FALSE, size = 'footnotesize', comment=NA, results='hold') knit_hooks$set(par = function(before, options, envir){ if (before && options$fig.show!='none') par(mar […]