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Exception: KeyError

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
Instance Chain:
Inherits: IndexError
Defined in: error.c,
error.c

Overview

Raised when the specified key is not found. It is a subclass of ::IndexError.

h = {"foo" => :bar}
h.fetch("foo") #=> :bar
h.fetch("baz") #=> KeyError: key not found: "baz"

Class Attribute Summary

::Exception - Inherited

.to_tty?

Returns true if exception messages will be sent to a tty.

Class Method Summary

::Exception - Inherited

.exception

With no argument, or if the argument is the same as the receiver, return the receiver.

.new

Construct a new ::Exception object, optionally passing in a message.

Instance Method Summary

::Exception - Inherited

#==

Equality—If obj is not an ::Exception, returns false.

#backtrace

Returns any backtrace associated with the exception.

#backtrace_locations

Returns any backtrace associated with the exception.

#cause

Returns the previous exception ($!) at the time this exception was raised.

#exception

With no argument, or if the argument is the same as the receiver, return the receiver.

#full_message

Returns formatted string of exception.

#inspect

Return this exception's class name and message.

#message

Returns the result of invoking exception.to_s.

#set_backtrace

Sets the backtrace information associated with exc.

#to_s

Returns exception's message (or the name of the exception if no message is set).

Constructor Details

.new(message = nil, receiver:nil, key:nil) ⇒ key_error

Construct a new KeyError exception with the given message, receiver and key.

[ GitHub ]

  
# File 'error.c', line 1810

static VALUE
key_err_initialize(int argc, VALUE *argv, VALUE self)
{
    VALUE options;

    rb_call_super(rb_scan_args(argc, argv, "01:", NULL, &options), argv);

    if (!NIL_P(options)) {
	ID keywords[2];
	VALUE values[numberof(keywords)];
	int i;
	keywords[0] = id_receiver;
	keywords[1] = id_key;
	rb_get_kwargs(options, keywords, 0, numberof(values), values);
	for (i = 0; i < numberof(values); ++i) {
	    if (values[i] != Qundef) {
		rb_ivar_set(self, keywords[i], values[i]);
	    }
	}
    }

    return self;
}

Instance Method Details

#keyObject

Return the key caused this KeyError exception.

[ GitHub ]

  
# File 'error.c', line 1781

static VALUE
key_err_key(VALUE self)
{
    VALUE key;

    key = rb_ivar_lookup(self, id_key, Qundef);
    if (key != Qundef) return key;
    rb_raise(rb_eArgError, "no key is available");
}

#receiverObject

Return the receiver associated with this KeyError exception.

[ GitHub ]

  
# File 'error.c', line 1764

static VALUE
key_err_receiver(VALUE self)
{
    VALUE recv;

    recv = rb_ivar_lookup(self, id_receiver, Qundef);
    if (recv != Qundef) return recv;
    rb_raise(rb_eArgError, "no receiver is available");
}