R 中的数字行摘要

Question

I just hope to learn how to make a simple statistical summary of the random numbers fra row 1 to 5 in R. (as shown in picture).

And then assign these rows to a single variable.

enter image description here

Hope you can help!

Answer 1

When you type something like 3 on a single line and ask R to "run" it, it doesn't store that anywhere -- it just evaluates it, meaning that it tries to make sense out of whatever you've typed (such as 3 , or 2+1 , or sqrt(9) , all of which would return the same value) and then it more or less evaporates. You can think of your lines 1 through 5 as behaving like you've used a handheld scientific calculator; once you type something like 300 / 100 into such a calculator, it just shows you a 3 , and then after you have executed another computation, that 3 is more or less permanently gone.

To do something with your data, you need to do one of two things: either store it into your environment somehow, or to "pipe" your data directly into a useful function.

In your question, you used this script:

1
3
2
7
6

summary()

I don't think it's possible to repair this strategy in the way that you're hoping -- and if it is possible, it's not quite the "right" approach. By typing the numbers on individual lines, you've structured them so that they'll evaluate individually and then evaporate. In order to run the summary() function on those numbers, you will need to bind them together inside a single vector somehow, then feed that vector into summary() . The "store it" approach would be

my_vector <- c(1, 3, 7, 2, 6)
summary(my_vector)

The importance isn't actually the parentheses; it's the function c() , which stands for concatenate , and instructs R to treat those 5 numbers as a collective object (ie a vector). We then pass that single object into my_vector() .

To use the "piping" approach and avoid having to store something in the environment, you can do this instead (requires R 4.1.0+):

c(1, 3, 7, 2, 6) |> summary()

Note again that the use of c() is required, because we need to bind the five numbers together first. If you have an older version of R, you can get a slightly different pipe operator from the magrittr library instead that will work the same way. The point is that this "binding" part of the process is an essential part that can't be skipped.

---

Now, the crux of your question: presumably, your data doesn't really look like the example you used. Most likely, it's in some separate.csv file or something like that; if not, hopefully it is easy to get it into that format. Assuming this is true, this means that R will actually be able to do the heavy lifting for you in terms of formatting your data.

As a very simple example, let's say I have a plain text file, my_example.txt , whose contents are

1
3
7
2
6

In this case, I can ask R to parse this file for me. Assuming you're using RStudio, the simplest way to do this is to use the File -> Import Dataset part of the GUI. There are various options dealing with things such as headers, separators, and so forth, but I can't say much meaningful about what you'd need to do there without seeing your actual dataset.

When I import that file, I notice that it does two things in my R console:

1. my_example <- read.table(...)
2. View(my_example)

The first line stores an object (called a "data frame" in this case) in my environment; the second shows a nice view of how it's rendered. To get the summary I wanted, I just need to extract the vector of numbers I want, which I see from the view is called V1 , which I can do with summary(my_example$V1) .

This example is probably not helpful for your actual data set, because there are so many variations on the theme here, but the theme itself is important: point R at a file, as it to render an object, then work with that object. That's the approach I'd recommend instead of typing data as lines within an R script, as it's much faster and less error-prone.

Hopefully this will get you pointed in the right direction in terms of getting your data into R and working with it.