R，将变量传递给系统命令 [英] R, passing variables to a system command

问题描述

使用 R，我希望创建一个二维码并将其嵌入到 Excel 电子表格(数百个代码和电子表格)中.显而易见的方法似乎是使用命令行创建二维码，并在 R 中使用系统"命令.有谁知道如何通过系统"命令传递 R 变量?Google 没有太大帮助，因为系统"有点笼统，?system 不包含任何此类示例.

Using R, I am looking to create a QR code and embed it into an Excel spreadsheet (hundreds of codes and spreadsheets). The obvious way seems to be to create a QR code using the command line, and use the "system" command in R. Does anyone know how to pass R variables through the "system" command? Google is not too helpful as "system" is a bit generic, ?system does not contain any examples of this.

注意 - 我实际上使用的是数据矩阵而不是 QR 码，但是在 R 问题中使用术语数据矩阵"会导致严重破坏，所以让我们改用 QR 码.:-)

Note - I am actually using data matrices rather than QR codes, but using the term "data matrix" in an R question will lead to havoc, so let's talk QR codes instead. :-)

system("dmtxwrite my_r_variable -o image.png")

失败，我尝试使用粘贴"的变体也是如此.感谢您收到任何建议.

fails, as do the variants I have tried with "paste". Any suggestions gratefully received.

推荐答案

假设我们有一个变量 x 我们想要传递给 dmtxwrite，你可以传递它就像:

Let's say we have the variable x that we want to pass on to dmtxwrite, you can pass it on like:

x = 10
system(sprintf("dmtxwrite %s -o image.png", x))

或者使用paste:

system(paste("dmtxwrite", x, "-o image.png"))

但在这种情况下我更喜欢 sprintf.

but I prefer sprintf in this case.

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