Class enthought.traits.trait_handlers.TraitList

API Reference for Enthought Tool Suite 2.7.1

Ensures that a value assigned to a trait attribute is a list containing elements of a specified type, and that the length of the list is also within a specified range.

TraitList also makes sure that any changes made to the list after it is assigned to the trait attribute do not violate the list's type and length constraints. TraitList is the underlying handler for the predefined list-based traits.

For example:

class Card(HasTraits):
    pass
class Hand(HasTraits):
    cards = Trait([], TraitList(Trait(Card), maxlen=52))

This example defines a Hand class, which has a cards trait attribute, which is a list of Card objects and can have from 0 to 52 items in the list.

Base classes
Attributes
Methods

Inherits from

TraitHandler: enthought.traits.trait_handlers.TraitHandler

Attributes

default_value_type
```
default_value_type = 5
```
info_trait
```
info_trait = None
```

Method summary

__init__(self, trait = None, minlen = 0, maxlen = sys.maxint, has_items = True)
clone(self)
get_editor(self, trait)
info(self)
items_event(self)
validate(self, object, name, value)

Methods

__init__(self, trait = None, minlen = 0, maxlen = sys.maxint, has_items = True)

Creates a TraitList handler.

Parameters

trait : trait

The type of items the list can contain

minlen : integer

The minimum length of the list

maxlen : integer

The maximum length of the list

has_items : boolean

Flag indicating whether the list contains elements

Description

If trait is None or omitted, then no type checking is performed on any items in the list; otherwise, trait must be either a trait, or a value that can be converted to a trait using the Trait() function.
clone(self)
get_editor(self, trait)
info(self)
items_event(self)
validate(self, object, name, value)

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