I just installed Ruby on my Ubuntu machine, and did this:
我刚刚在我的Ubuntu机器上安装了Ruby，并做到了:
$ ruby --version
ruby 1.9.3p0 (2011-10-30 revision 33570) [i686-linux]
$ ruby
p File.basename("foo")
p File.exist("foo")
"foo"
-:2:in `<main>': undefined method `exist' for File:Class (NoMethodError)
The way I read the File documentation page, shouldn't this work?
我读取文件文档页面的方式，不应该这样吗?
1 个解决方案
#1
8
You forgot the question mark (?) at the end:
你忘了最后的问号(?)
File.exist? 'foo'
File.exists? 'foo'
In general, methods which answer questions will always end with a question mark.
一般来说，回答问题的方法总是以问号结尾。
In this case, the method is asking File the does 'foo' exist? question. The class will return the answer.
在这种情况下，方法是问文件是否存在foo ?的问题。课程将返回答案。
#1
8
You forgot the question mark (?) at the end:
你忘了最后的问号(?)
File.exist? 'foo'
File.exists? 'foo'
In general, methods which answer questions will always end with a question mark.
一般来说，回答问题的方法总是以问号结尾。
In this case, the method is asking File the does 'foo' exist? question. The class will return the answer.
在这种情况下，方法是问文件是否存在foo ?的问题。课程将返回答案。