遍历数据而不是在R中建立索引

我正在尝试使用Rmarkdown将数据转换为html文档，并且目前依靠转换为矢量和索引来解决我的问题。

尽管我的样本数据有4个观测值，但我的实际数据集却有30多个记录，因此索引似乎很麻烦且不自然。

是否有更好的方法按顺序提取这些元素？任何建议都很好。

 --
title: "Rmarkdown report"
output: html_document
---
    
    
```{r echo = FALSE}
mydata <- data.frame(First = c("John", "Hui", "Jared"), Second = c("Smith", "Chang", "Jzu"), Sport = c("Football","Soccer","Ballet"), Age = c("12", "13", "12"), submission =     c("Microbes may be the friends of future colonists living off the land on the moon, Mars or elsewhere in the solar system and aiming to establish self-sufficient homes. Space     colonists, like people on Earth, will need what are known as rare earth elements, which are critical to modern technologies. These 17 elements, with daunting names like yttrium,     lanthanum, neodymium and gadolinium, are sparsely distributed in the Earths crust. Without the rare earths, we wouldn’t have certain lasers, metallic alloys and powerful magnets that     are used in cellphones and electric cars. But mining them on Earth today is an arduous process. It requires crushing tons of ore and then extracting smidgens of these metals using     chemicals that leave behind rivers of toxic waste water.",

"Experiments conducted aboard the International Space Station show that a potentially cleaner, more efficient method could work on other worlds: let bacteria do the messy work of     separating rare earth elements from rock. The idea is the biology is essentially catalyzing a reaction that would occur very slowly without the biology, said Charles S. Cockell, a     professor of astrobiology at the University of Edinburgh.
On Earth, such biomining techniques are already used to produce 10 to 20 percent of the world’s copper and also at some gold mines; scientists have identified microbes that help     leach rare earth elements out of rocks.",
"Experiments conducted aboard the International Space Station show that a potentially cleaner, more efficient method could work on other worlds: let bacteria do the messy work of     separating rare earth elements from rock. The idea is the biology is essentially catalyzing a reaction that would occur very slowly without the biology, said Charles S. Cockell, a     professor of astrobiology at the University of Edinburgh.
On Earth, such biomining techniques are already used to produce 10 to 20 percent of the world’s copper and also at some gold mines; scientists have identified microbes that help     leach rare earth elements out of rocks."))
    

    
first<- as.vector(mydata$First)
sec <- as.vector(mydata$Second)
age <- as.vector(mydata$Age)
submission <- as.vector(mydata$submission)

```
    
    
    
    
## 

**First:** `r first[1]` &emsp; **Second:**  `r sec[1]` <br>
**Age:** `r age[1]`    


**submission** <br>

`r submission[1]`


***

**First:** `r first[2]` &emsp; **Second:**  `r sec[2]` <br>
**Age:** `r age[2]`    


**submission** <br>

`r submission[2]`