在Ruby中,数据类型转换可能会遇到以下问题: 类型错误(TypeError):当你尝试将一个数据类型转换为另一个不兼容的数据类型时,会引发TypeError。例如,将字符串转换为数字或布尔值时,可能会出现这种错误。 # 示例:将字符串转换为数字 num = "123" puts num + 5 # TypeError: can't convert String to Integer 复制...
convert a value to another representation. The most common methods in this category are to_s, to_i, to_f, and to_a to convert to String, Integer, Float, and Array, respectively. Built-in methods do not typically invoke these methods for you. If you invoke a method that expects a Str...
p Float(nil) # => 0.0 # ruby1.7特性: cannot convert nil into Float (TypeError) p Float(Object.new) # => cannot convert Object into Float (TypeError) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. Integer(arg) 将参数变为整数(Fixnum,Bignum)并返回结果....
to convert the argument with to_s. (Values interpolated into double-quoted strings, however, are automatically converted with to_s.) 内建的方法通常不会自动调用。如果你调用一个参数为String的方法,却传递一个其他类型的对象给它,该方法是不会主动调用参数的to_s方法来进行转换的。(然后,对于那些内插在...
TypeError: no implicit conversion of String into Integer from /home/alan/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/jwt-1.5.6/lib/jwt.rb:88:in []' from /home/alan/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/jwt-1.5.6/lib/jwt.rb:88:in encoded_payload' from /home/alan/...
Methods in Ruby are allowed to return more than one value, and parallel assignment is helpful in conjunction with such methods. For example: # Define a method to convert Cartesian (x,y) coordinates to Polar def polar(x,y) theta = Math.atan2(y,x) # Compute the angle ...
String Interpolation How to Extract a Substring How to convert String to lower or upper case Helpful methods Integer Helpful methods Range Helpful methods How to use step with Range Methods How to declare a method How to call a method How to define a default value for a method parameter...
small_duration_from_string = ActiveSupport::Duration.build('9') # => TypeError (can't build an ActiveSupport::Duration from a String) *Alexei Emam* * Add `ActiveSupport::Cache::Store#delete_multi` method to delete multiple keys from the cache store. ...
: * Signal.signame(signo) -> string * convert signal numberto signal name * * Signal.trap" { |signo| putsSignal.signame(signo) } * Processkill"INT", 0) * * <em>produces:</em> * * INT */ static VALUE sig_signame(VALUE recv, VALUE signo ...
Ruby支持的数据类型包括基本的Number、String、Ranges、Symbols,以及true、false和nil这几个特殊值,同时还有两种重要的数据结构——Array和Hash。 数字 Ruby 中所有的数字都是 Numberic 类的实例,所有整数都是 Integer 的实例。Fixnum 和 Bignum之间的转换是透明的。Ruby 利用 Float 来近似的表示实数,该类会利用本地平...