一步一步学Ruby(二十): 文件使用
一、
新建文件
f=File.new(File.join("C:","Test.txt"), "w+")
f.puts("I am Jack")
f.puts("Hello World")
文件模式
"r" ：Read-only. Starts at beginning of file (default mode).
"r+" ：Read-write. Starts at beginning of file.
"w" ：Write-only. Truncates existing file to zero length or creates a new file for writing.
"w+" ：Read-write. Truncates existing file to zero length or creates a new file for reading and writing.
"a" ：Write-only. Starts at end of file if file exists; otherwise, creates a new file for writing.
"a+" ：Read-write. Starts at end of file if file exists; otherwise, creates a new file for reading and writing.
"b" ：(DOS/Windows only.) Binary file mode. May appear with any of the key letters listed above
二、读取文件
file=File.open(File.join("C:","Test.txt"),"r")
file.each { |line| print "#{file.lineno}.", line }
file.close
输出：
1.白日依山尽
2.黄河入海流
3.欲穷千里目
4.更上一层楼
三、新建、删除、重命名文件
File.new( "books.txt", "w" ) File.rename( "books.txt", "chaps.txt" ) File.delete( "chaps.txt" )
三、目录操作
创建目录
Dir.mkdir("c:/testdir")
#删除目录
Dir.rmdir("c:/testdir")
#查询目录里的文件
p Dir.entries(File.join("C:","Ruby")).join(' ')
#遍历目录
Dir.entries(File.join("C:","Ruby")).each {
|e| puts e
}
输出：
"C:/studyruby" "c:/ruby"
查看目录信息
d:\Study\rubysample>irb
irb(main):001:0> dir=Dir.open( File.join("C:","Ruby") )
=> #
irb(main):002:0> dir.path
=> "C:/Ruby"
irb(main):003:0> dir.tell
=> 0
irb(main):004:0> dir.read
=> "."
irb(main):005:0> dir.rewind
=> #
irb(main):006:0> dir.each{|e| puts e}
.
..
bin
ChangeLog.txt
doc
lib
LICENSE.txt
man
MANIFEST
misc
README.1st
ReleaseNotes.txt
ruby.ico
rubyopt.del
rubyw.ico
samples
scite
share
src
uninstall.exe
=> #
irb(main):007:0>