R基础绘图教程：如何将文本字符类型数据设置为X轴标签

核心报错诱因 #

你当前的Countries列实际是列表类型，并非普通字符向量。你用lapply做类型转换时，lapply默认返回列表结构，导致plot()函数无法识别分类轴的坐标值，才触发need finite 'xlim' values报错。
你可以运行class(Finally$Countries)验证，输出会是list而非character。

修复步骤 #

第一步：修正Countries列的数据类型 #

在预处理代码最后加一行，把列表列转成普通字符向量即可：

Finally$Countries <- unlist(Finally$Countries)

如果需要固定分类轴的显示顺序，也可以转成因子（默认按数据现有顺序排列）：

Finally$Countries <- factor(unlist(Finally$Countries), levels = unique(unlist(Finally$Countries)))

第二步：修正绘图代码 #

R基础绘图原生支持分类X轴，考虑到国家名称较长容易重叠，调整后的完整绘图代码如下：

# 调大下边距，避免国家名被截断
par(mar = c(12, 4, 4, 4) + 0.3)
# 绘制第一个指标，先关闭默认X轴输出方便自定义
plot(x = Finally$Countries, y = Finally$RobberyPerCent, 
     pch = 16, col = 2, xaxt = "n",
     xlab = "国家", ylab = "RobberyPerCent")
# 自定义X轴刻度，文字旋转90度避免重叠
axis(side = 1, at = 1:nrow(Finally), labels = Finally$Countries, las = 2, cex.axis = 0.7)
# 叠加第二个指标
par(new = TRUE)
plot(x = Finally$Countries, y = Finally$UnlawfulPerCent, 
     pch = 17, col = 3, axes = FALSE, xlab = "", ylab = "")
# 添加右侧第二Y轴
axis(side = 4, at = pretty(range(Finally$UnlawfulPerCent)))
mtext("UnlawfulPerCent", side = 4, line = 3)
# 添加图例区分两个指标
legend("topright", legend = c("RobberyPerCent", "UnlawfulPerCent"), 
       pch = c(16,17), col = c(2,3))

内容的提问来源于stack exchange，提问作者iKcon