Ruby常用文件操作代码实例

#建立一个222.rb文件并且输入字符

file = File.open("222.rb","w+")

file.puts "123\nwadwa\n12124124\ndwdw"

file.close

 

 

#输出222.rb的内容

File.open("222.rb","r+") do |file|

while line = file.gets

puts line

end

end

 

 

#直接用IO操作文件

IO.foreach("222.rb") do |line|

puts line if line =~/abc/ #输出匹配到了'abc'的所在行

puts line if line !~/qwe/ #输出没有匹配到'qwe'的所在行

end

 

 

 

#输出文件的绝对路径

puts File.expand_path("222.rb")

 

 

#count chars from a file

file= File.new("222.rb")

w_count = 0

file.each_byte do |byte|

w_count += 1 if byte ==?1

end

puts "#{w_count}"

 

 

#create new file and write some words there

print "The file now is exist? --> "

puts File.exist?("asd.txt")#判断文件是否存在

 

file= File.new("asd.txt","w")

print "The file now is exist? --> "

puts File.exist?("asd.txt")

 

file.write("hehe\nhahah")

 

 

#io.stream operation

require 'stringio'

ios = StringIO.new("abcdef\n ABC \n 12345")

ios.seek(5) #把偏移指针移到5（e字母所在位置）

ios.puts("xyz3") #从5开始覆写原有数据

puts ios.tell #tell--Returns the current offset (in bytes) of ios. 

puts ios.string

puts ios.string.dump #忽略\n的转义

 

 

#another example

require 'stringio'

ios = StringIO.new("abcdef\nq9ert \n 12345")

ios.seek(3)

ios.ungetc(?w) #replace the char at index 3

puts "Ptr = #{ios.tell}"

s1 = ios.gets #filte the "\n" 

s2 = ios.gets

puts s1

puts s2

 

 

#Ruby打开文件并写入数据操作

txt = File.open("文件路径","w+")

txt.puts '要写入的文件内容'

txt.close

#从文件里读取数据

num = File.readlines("文件路径")[0].chomp

#打开文件的方法

system("notepad 文件路径")