摘要: a = matrix(1:20, nrow = 4,dimnames = list(c("第1行", "第2行", "第3行", "第4行"), c("第1列", "第2列", "第3列", "第4列", "第5列"))) a a[c(1, 3), c(2, 4)] a[c(1, 3),] a[, 阅读全文
posted @ 2020-06-22 14:55 月光边境Eric 阅读(143) 评论(0) 推荐(0) 编辑