Question

我正在学习“学习Ruby The Hard Way”，而且我一直在清理代码。当我运行ori代码时，它不会产生任何错误。当我使用更改运行我的代码时，它会运行所有内容，但也会添加错误消息。我不太清楚为什么。请帮忙。

ex17.rb:19:in `<main>': undefined method `close' for #<String:0x007febe4054c18> (NoMethodError)

ori的

from_file, to_file = ARGV
script = $0 

puts "Copying from #{from_file} to #{to_file}"

#we could do these two on one line too, how?
input = File.open(from_file)
indata = input.read()

puts "The input file is #{indata.length} bytes long"

puts "Does the output file exist? #{File.exist? to_file}"

output = File.open(to_file, "w")
output.write(indata)

puts "Alright, all done."

output.close()
input.close()

我所做的更改是将输入和indata放在一起。

from_file, to_file = ARGV
script = $0 

puts "Copying from #{from_file} to #{to_file}"

#we could do these two on one line too, how?
input = File.open(from_file).read()

puts "The input file is #{input.length} bytes long"

puts "Does the output file exist? #{File.exist? to_file}"

output = File.open(to_file, "w")
output.write(input)

puts "Alright, all done."

output.close()
input.close()

Answer 1

在第一个代码的第input = File.open(from_file)行中，input的类型为File。

但在第二个代码中，input = File.open(from_file).read()行input的类型为String。并且String没有close方法。

通过传递output.close和input.close将2个变量更改为1

1 个答案: