使用R中的脚本生成pdf时出错

Question

我正在使用R循环遍历数据框的列,并绘制结果分析图.脚本运行时我没有收到任何错误,但它生成了一个无法打开的pdf.

如果我运行脚本的内容,它可以正常工作.我想知道循环的速度是否有问题,所以我试图强迫它暂停.这似乎没有什么区别.我对人们有任何建议感兴趣,而且我对R也很陌生,所以我也欢迎提出如何改进方法的建议.谢谢.

for (i in 2:22) {

  # Organise data
  pop_den_z = subset(pop_den, pop_den[i] != "0")  # Remove zeros
  y = pop_den_z[,i]        # Get y col
  x = pop_den_z[,1]        # get x col
  y = log(y)               # Log transform

  # Regression
  lm.0 = lm(formula = y ~ x)                # make linear model
  inter = summary(lm.0)$coefficients[1,1]   # Get intercept
  slop = summary(lm.0)$coefficients[2,1]    # Get slope

  # Write to File
  a = c(i, inter, slop)
  write(a, file = "C:/pop_den_coef.txt", ncolumns = 3, append = TRUE, sep = ",")

  ## Setup pdf
  string = paste("C:/LEED/results/Images/R_graphs/Pop_den", paste(i-2), "City.pdf")
  pdf(string, height = 6, width = 9)

  p <- qplot(
    x, y,
    xlab = "Radius [km]",
    ylab = "Population Density [log(people/km)]",
    xlim = x_range,
    main = "Analysis of Cities"
  )

  # geom_abline(intercept,slope)
  p + geom_abline(intercept = inter, slope = slop, colour = "red", size = 1)

  Sys.sleep(5)

  ### close the PDF file
  dev.off()
}

Answer 1

这条线应该是

print(p + geom_abline(intercept = inter, slope = slop, colour = "red", size = 1))

在pdf设备中,ggplot(和lattice)仅在显式打印时写入文件.