读取多个文本文件

Question

I am reading the attached .txt file using the R code below. I have 2200 txt files like this with different station IDs. I need to output only the year for peak flow data available. For example,

Year     Peak 
1929   4050 
1940   7000 
1958   4050 
... 

Can somebody help me to modify this code to achive this.

My R code is shown below.

rm(list=ls(all=TRUE)) 
iPath <- 'C:/Desktop/flow_raw/Region-03/' 
mydata <- read.table("02053200-PeakFlow-uptoWY2015.txt", sep="\t", header=TRUE) 
out <- mydata[c(3,5)] 

Answer 1

I cannot see any attached file.

There are various options to accomplish the task.

library(plyr)   #you only need these packages if you follow my first Option
library(dplyr)

files <- dir("C:/Desktop/flow_raw/Region-03", 
             full.names = TRUE)


# OPT. 1: if you need a Data Frame
df <- lapply(files, function(x) 
      read.table(x, sep = '\t', header = FALSE)[c(3,5)]) %>% 
      plyr::ldply()    #the '.id' argument might be useful

# OPT. 2: if you need a list
listTxt <- lapply(files, function(x) 
           read.table(x, sep = '\t', header = FALSE)[c(3,5)])

NB: If you need a FAST reading function, please, take a look at

data.table::fread

Answer 2

If I am understanding your question correctly, you want to import 2200 text files at once. For some reason I can't see the attachment, but you should be able to read in the data using the function Corpus from the tm package.

In your case: (the path should lead to a folder where all the text files live)

TextCorpus <- Corpus(DirSource("C:/Desktop/flow_raw/Region-03"))
TextCorpus$content 

You should be able to subset these documents. I usually make a list of the documents' content so that you would have a list of 2200 elements containing the original text.