05-11-In-class exercises-4

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library(animation)
library(gganimate)

## Loading required package: ggplot2

#跑了這動畫跑非常久，不得以參考KY同學的將張數下修

Brownian <- function(n = 11, pause = 0.05, nIter = 64, ...) {
    x = rnorm(n)
    y = rnorm(n)
    i = 1
    while (i <= nIter) {
        plot(x, y, ...)
        text(x, y, cex = 0.5)
        x = x + rnorm(n)
        y = y + rnorm(n)
        Sys.sleep(pause)
        i = i + 1
    }
} 

saveGIF(Brownian(xlim = c(-20, 20), ylim = c(-20, 20),pch = 21, cex = 2, col = "cyan", bg = "lavender"))

## Output at: animation.gif

## [1] TRUE

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test it

/Users/Tjlee/Desktop/weather/animation.gif

##此作法參考KY跟Chang, C. Y.兩位同學再進行微調
Brownian2 <- function(n = 11, pause = 0.05,nIter = 8, ...) {
    x = rnorm(n) 
    y = rnorm(n) 
    i = 1
    repeat {
      if(i > nIter) break # 重複做，一旦大於8就停止
        plot(x, y, ...)
        text(x, y, cex = 0.5)
        x = x + rnorm(n)
        y = y + rnorm(n)
        Sys.sleep(pause)
        i = i + 1
    }
} 
Brownian2(xlim = c(-20, 20), ylim = c(-20, 20),pch = 21, cex = 2, col = "cyan", bg = "lavender")

##由於不太會改fcn，因此先去理解他。
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