caterva2.lazyexpr

caterva2.lazyexpr(name, expression, operands, urlbase=None, auth_cookie=None)

Creates a lazy expression dataset in personal space.

A dataset with the specified name will be created or overwritten if already exists.

Parameters:

• name (str) – Name of the dataset to be created (without extension).

• expression (str) – Expression to be evaluated, which must yield a lazy expression.

• operands (dict) – Mapping of variables in the expression to their corresponding dataset paths.

• urlbase (str, optional) – Base URL to query. Default to caterva2.sub_urlbase_default.

• auth_cookie (str, optional) – HTTP cookie for authorization. Must be provided unless specified in a :py_obj:`caterva2.c2context`.

Returns:

Path of the created dataset.

Return type:

Path

Examples

>>> import caterva2 as cat2
>>> import numpy as np
>>> # To create a lazyexpr you need to be a registered used
>>> urlbase = 'https://cat2.cloud/demo'
>>> auth_cookie = cat2.get_auth_cookie(urlbase, dict(username='user@example.com', password='foo'))
>>> src_path = f'@personal/dir{np.random.randint(0, 100)}/ds-4d.b2nd'
>>> path = cat2.upload('root-example/dir1/ds-2d.b2nd', src_path, urlbase, auth_cookie)
>>> cat2.lazyexpr('example-expr', 'a + a', {'a': path}, urlbase, auth_cookie)
PosixPath('@personal/example-expr.b2nd')
>>> 'example-expr.b2nd' in cat2.get_list('@personal', urlbase, auth_cookie)
True