ggplot2覆蓋保存在列表中的情節

Question

我有一個代碼來繪製數據框中的一些數據。 當我運行沒有循環的代碼時，它可以工作，但是當我使用代碼執行代碼時，然後執行plots[[1]]plots[[2]]所有的圖都是相同的，但實驗室是不同的。

我在做什麼錯了？由於

#-- Plots 
plots <- list() 
combinations <- combn(dim(ssgsea.diff)[2],2) 

for (i in 1:dim(combinations)[2]){ 

    fit <- lm(ssgsea.diff[,combinations[1,i]] ~ ssgsea.diff[,combinations[2,i]], 
      data = ssgsea.diff) 

    plot1 <- ggplot(ssgsea.diff) + 
    aes(ssgsea.diff[,combinations[1,i]], ssgsea.diff[,combinations[2,i]]) + 
    geom_point() 

    plot1 <- plot1 + 
    labs(x = names(ssgsea.diff)[combinations[1,i]], 
     y = names(ssgsea.diff)[combinations[2,i]]) + 
    geom_smooth(method="lm", col = "red") + 
    labs(title = paste("Adj R2 = ", signif(summary(fit)$adj.r.squared, 5), 
         " Slope =",signif(fit$coef[[2]], 5), 
         " Pval =",signif(summary(fit)$coef[2,4], 5))) 

    plots[[i]] <- plot1 
} 

Answer 1

由於沒有提供數據，我會試圖用R A共同數據，以證明：

data(airquality) 
ssgsea.diff <- as.data.frame(airquality) 

plots <- list() 
combinations <- combn(dim(ssgsea.diff)[2],2) 

使用原來的代碼重現問題。有後的15個地塊for循環的完成，&實際上他們都有着不同的標籤在同一張圖：

for (i in 1:dim(combinations)[2]){ 

    fit <- lm(ssgsea.diff[,combinations[1,i]] ~ ssgsea.diff[,combinations[2,i]], 
      data = ssgsea.diff) 

    plot1 <- ggplot(ssgsea.diff) + 
    aes(ssgsea.diff[,combinations[1,i]], ssgsea.diff[,combinations[2,i]]) + 
    geom_point() 

    plot1 <- plot1 + 
    labs(x = names(ssgsea.diff)[combinations[1,i]], 
     y = names(ssgsea.diff)[combinations[2,i]]) + 
    geom_smooth(method="lm", col = "red") + 
    labs(title = paste("Adj R2 = ", signif(summary(fit)$adj.r.squared, 5), 
         " Slope =",signif(fit$coef[[2]], 5), 
         " Pval =",signif(summary(fit)$coef[2,4], 5))) 

    plots[[i]] <- plot1 
} 

解決方案下面將導致存儲在列表中15個不同地塊（我還定義列索引首先，爲了使代碼更易讀）：

for (i in 1:dim(combinations)[2]){ 

    # define column indices & column names first 
    C1 <- combinations[1, i]; C1.name <- names(ssgsea.diff)[C1] 
    C2 <- combinations[2, i]; C2.name <- names(ssgsea.diff)[C2] 

    fit <- lm(ssgsea.diff[, C1] ~ ssgsea.diff[, C2]) # no need to specify data here 

    plot1 <- ggplot(ssgsea.diff) + 
    aes_string(C1.name, C2.name) + geom_point() 

    plot1 <- plot1 + 
    labs(x = C1.name, y = C2.name) + 
    geom_smooth(method="lm", col = "red") + 
    labs(title = paste("Adj R2 = ", signif(summary(fit)$adj.r.squared, 5), 
         " Slope =", signif(fit$coef[[2]], 5), 
         " Pval =", signif(summary(fit)$coef[2, 4], 5))) 

    plots[[i]] <- plot1 
} 

rm(C1, C2, C1.name, C2.name, fit, plot1, i) 

說明：由於您指定ggplot審美映射的方式，所有的情節的對象是在當前循環結束時評估（即啦st）值爲i。更安全的方法是利用ggplot中的參數data，該參數將數據幀存儲在ggplot對象本身中，作爲拷貝而不是參考。當每個循環改變i時，ggplot對象中的數據副本不會改變。這兩篇文章的答案進一步討論了這一點：Storing ggplot objects in a list from within loop in R & Storing plot objects in a list。