使用系统 pause/sleep 逐步绘制

Question

我有以下代码，但它没有按预期工作。

for(i in 3:nrow(pima_diabetes_kmean)){
  k.means.fit <- kmeans(pima_diabetes_kmean[1:i, c("Pregnancy", "Age")], 2)
  plot(
    pima_diabetes_kmean[1:i, c("Pregnancy", "Age")],
    col = alpha(k.means.fit$cluster, 0.2),
    pch = 20,
    cex = 3, main = "Clusters predicted by models"
  )
  points(
    k.means.fit$centers,
    pch = 4,
    cex = 4,
    lwd = 4,
    col = "blue"
  )
  Sys.sleep(0.001)
}

我可以删除循环并一次绘制所有内容。但是我想绘制前 3 行数据，然后是 0.001s 间隔后的 4 行，然后是 5 行，依此类推。它最终将绘制所有数据点。

我想捕捉这个过程，这样我就可以创建一个视频或 gif 来展示每个点的添加是如何影响聚类的。但是这个图是一次绘制，而不是逐步绘制，就好像 for 循环不存在一样。

Answer 1

这是它的工作原理：

png(file="kMeanPlot%03d.png", width=719, height=539)
for(i in seq(3, nrow(pima_diabetes_kmean), by = 20)){
  k.means.fit <- kmeans(pima_diabetes_kmean[1:i, c("Pregnancy", "Age")], 2)
  plot(
    pima_diabetes_kmean[1:i, c("Pregnancy", "Age")],
    col = alpha(k.means.fit$cluster, 0.2),
    pch = 20,
    cex = 3, main = "Clusters predicted by models"
  )
  points(
    k.means.fit$centers,
    pch = 4,
    cex = 4,
    lwd = 4,
    col = "blue"
  )
}
dev.off()

# convert the .png files to one .gif file using ImageMagick. 
# The system()/shell() function executes the command as if it was done
# in the terminal. the -delay flag sets the time between showing
# the frames, i.e. the speed of the animation.
# You will need to install the imagemagick for this
# Following command for non-windows OS
# system("C:/Program Files/ImageMagick-7.0.5-Q16/convert -delay 80 *.png fucked.gif") 
# Following command for Windows OS
shell("convert -delay 40 *.png kMeanPlot.gif")

# to not leave the directory with the single png files I remove them.
file.remove(list.files(pattern="[kMeanPlot]*.png"))

使用系统 pause/sleep 逐步绘制

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