通過傳遞output.close和input.close將2個變量更改爲1

Question

我正在通過Learn Ruby The Hard Way和我被困在清理代碼的過程中。當我運行ori代碼時，它不會產生任何錯誤。當我使用更改運行代碼時，它會運行所有內容，但也會添加錯誤消息。我不太清楚爲什麼。請幫忙。

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

ori。

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() 

我所做的更改是將輸入和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

在第一代碼

中，管線input = File.open(from_file)，的input類型是File。

但在第二個代碼中，行input = File.open(from_file).read()input的類型是String。並且String沒有close方法。