一步一步学Ruby(二十): 文件使用

一、新建文件

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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

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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

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File.new( "books.txt", "w" ) File.rename( "books.txt", "chaps.txt" ) File.delete( "chaps.txt" )

三、目录操作

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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：

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1 2	"C:/studyruby" "c:/ruby"

查看目录信息

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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>