英文:
Is the order always kept and respected when programming in R?
问题
我理解的是，当我有一个包含10行的矩阵或数据框时，如果它是新创建的，行名称会从1到10。我想确保，如果我输入一个具有给定名称的向量（如：c("Jhon", "Molly", ... "Lucy")），它将按照我考虑的顺序严格应用（1被替换为"Jhon"，一直到10被替换为"Lucy"），还是它会随机地用向量中的任何名称替换每一行？
英文:
What I mean is that when I have a matrix or data frame with 10 rows, if it's newly created row names go from 1 to 10. I want to make sure that if I type a vector with given names (like: c("Jhon","Molly",..."Lucy") it is going to be applied strictly in order as I think about it (1 being replaced by "Jhon" until 10 is replaced by "Lucy") or it could randomly replace each row with any name on my vector?
答案1
得分: 0
v1[numvec]
如果我们使用 row.names 来替换数值，请确保将其更改为 numeric，使用 as.numeric，否则它将是一个 character 类型，进行不同的匹配
数据
v1 <- c("Jhon", "Molly", "Jolly", "Holy", "Loly", "Solly", "Tolly",
"Dolly", "Hally", "Lucy")
set.seed(24)
numvec <- sample(10, 50, replace = TRUE)
英文:
We can use the numbers as index
v1[numvec]
If we use row.names to replace value, make sure to change it to numeric with as.numeric or else it is a character class and would do a different matching
data
v1 <- c("Jhon", "Molly", "Jolly", "Holy", "Loly", "Solly", "Tolly",
"Dolly", "Hally", "Lucy")
set.seed(24)
numvec <- sample(10, 50, replace = TRUE)
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论