throw

throw(e)

Throw an object as an exception

Examples

In the Julia programming language, the function throw(e) is used to throw an object as an exception.

julia> throw(DomainError("Invalid input"))
ERROR: DomainError with message Invalid input
Stacktrace:
 [1] top-level scope
   @ REPL[1]:1

Here are some common examples of using throw:

Throw a custom exception:

julia> throw(ArgumentError("Invalid argument"))
ERROR: ArgumentError: Invalid argument
Stacktrace:
[1] top-level scope
  @ REPL[1]:1

This example throws an ArgumentError with the message "Invalid argument".

Throw an exception with additional information:

julia> value = -5;
julia> if value < 0
          throw(DomainError("Value cannot be negative", value))
      end
ERROR: DomainError with message Value cannot be negative
Value:
-5
Stacktrace:
[1] top-level scope
  @ REPL[2]:2

In this example, a DomainError is thrown with the message "Value cannot be negative" and the value -5 is attached to the exception for additional information.

Common mistake example:

julia> throw("Invalid input")
ERROR: MethodError: no method matching throw(::String)
Closest candidates are:
  throw(::Any, ::Any...) at exceptions.jl:104
Stacktrace:
 [1] top-level scope
   @ REPL[1]:1

In this example, a string is directly passed to throw, which results in a MethodError. The correct usage is to pass an exception object instead of a string as an argument to throw.

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throw

Examples

See Also

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