How to understand symbols in Ruby - Stack Overflow
2010年2月26日 · :ruby is the symbol :ruby and that's all there is to it. It doesn't contain a value, it doesn't do anything, it just exists as the symbol :ruby. The symbol :ruby is a value just like the number 1 is. It doesn't point to another value any more than the number 1 does.
syntax - What is Ruby's double-colon `::`? - Stack Overflow
2010年6月10日 · As Matz delineates in his book, 'The Ruby Programming Language', constant lookup has multiple steps. First, it searches a constant in the lexical scope where the constant is referenced. If it does not find the constant within the lexical scope, it then searches the inheritance hierarchy. Because of this constant lookup algorithm, below we get ...
Is there a Python equivalent to Ruby symbols? - Stack Overflow
2010年9月18日 · Also for those interested: symbols in Ruby when used in a hash are very similar to empty objects in python. For example you could do: some_var = object() and then set a dictionary key as some_var: some_dict = { some_var : 'some value' } and then do a standard retrieval: some_dict[some_var]
Difference between "and" and && in Ruby? - Stack Overflow
2012年5月18日 · I don't know if this is Ruby intention or if this is a bug but try this code below. This code was run on Ruby version 2.5.1 and was on a Linux system. puts 1 > -1 and 257 < 256 # => false puts 1 > -1 && 257 < 256 # => true
How to call shell commands from Ruby - Stack Overflow
This explanation is based on a commented Ruby script from a friend of mine. If you want to improve the script, feel free to update it at the link. First, note that when Ruby calls out to a shell, it typically calls /bin/sh, not Bash. Some Bash syntax is not supported by /bin/sh on all systems. Here are ways to execute a shell script:
How to convert a string to lower or upper case in Ruby
2016年8月22日 · Ruby has a few methods for changing the case of strings. To convert to lowercase, use downcase: "hello James!".downcase #=> "hello james!"
What does the % operator do in Ruby in N - 2? - Stack Overflow
2010年8月18日 · Also keep in mind that, Ruby's definition of the modulo (%) operator differs from that of C and Java. In Ruby, -7%3 is 2. In C and Java, the result is -1 instead. In Ruby, the sign of the result (for % operator) is always the same as the sign of the second operand.
ruby - Installing RubyGems in Windows - Stack Overflow
Make sure that you check "Add ruby ... to your PATH". Now you can use "ruby" in your "cmd". If you installed ruby 1.9.3 I expect that the ruby is downloaded in C:\Ruby193. Installing Gem. install Development Kit in rubyinstaller. Make new folder such as C:\RubyDevKit and unzip. Go to the devkit directory and type ruby dk.rb init to generate ...
What is the difference between include and extend in Ruby?
2008年10月1日 · Just getting my head around Ruby metaprogramming. The mixin/modules always manage to confuse me. include: mixes in specified module methods as instance methods in the target class; extend: mixes in specified module methods as class methods in the target class; So is the major difference just this or is a bigger dragon lurking? e.g.
What's the difference between a low-level, midlevel, and high-level ...
The higher level languages involve more symbolism and constructs that are supposed to be closer to how humans normally think. C (and somewhat C++) has a reputation as being somewhat a hybrid low/high level because it has many constructs that are in high level languages, but also has instructions (e.g. shifts) that are low level languages but ...