Ref: R 字符串
Ref: R语言遍历文件和批量输出文件
head(x, n)Returns the first or last parts of a vector, matrix, table, data frame or function. Since head() and tail() are generic functions, they may also have been extended to other classes.
This function is similar to df.head(n)in python.
nchar(x)It takes a character vector as an argument and returns a vector whose elements contain the sizes of the corresponding elements of x.
length(x)Get or set the length of vectors (including lists) and factors, and of any other R object for which a method has been defined.
This function is similar to len(x)in python.
toupper()/tolower()
substring(x, start, stop)Extract or replace substrings in a character vector.
list.files(path = ".", pattern = NULL, all.files = FALSE,It produces a character vector of the names of files or directories in the named directory.
full.names = FALSE, recursive = FALSE,
ignore.case = FALSE, include.dirs = FALSE, no.. = FALSE)
list.dirs()
If wanting to batch files, forloop can be used as follows,
for (i in 1:length(files)) {
file = read.table(files[i], sep='\t')
}for (i in 1:length(files)) {
file = read.table(files[i], sep='\t')
}