如何在for循环中使用粘贴? [英] How to use paste with for-loops?

问题描述

我试图循环使用库 stringi 中的函数 stri_join ，但是遇到了困难.我想获得"A_1.png"，"A_2.png"，"A_3.png"，"A_4.png"，"A_5.png"，依此类推，直到获得"A_200.png".

I am trying to use the function stri_join, from the library stringi in a loop, but I am having difficulties. I would like to obtain "A_1.png", "A_2.png", "A_3.png", "A_4.png", "A_5.png", and so on until "A_200.png".

这是我的尝试:

 x <- c(1:200)
 x
 for (i in 1:length(x)){
   Names <-paste("A_", 1:length(i), ".png",sep = "")
   print(Names)
 }

我获得了"A_1.png"200次如果您能指出我所缺少的.

I obtain "A_1.png" 200 times. If you could point what I am missing.

推荐答案

我们不需要循环，因为 paste 是矢量化的.因此，要么使用 sprintf

We don't need a loop for this as paste is vectorized. So either use sprintf

Names <- sprintf("A_%d.png", x)

或粘贴

Names <- paste0("A_", x, ".png")

---

如果这是for循环的练习，初始化'Names'向量并将'Names'的每个元素分配给paste

---

If this is an exercise on for loop, initialize the 'Names' vector and assign each element of 'Names' to the corresponding value from paste

Names <- character(length(x))
for(i in seq_along(x)){
  Names[i] <- paste0("A_", i, ".png") 
}

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