caterva2.lazyexpr

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

Create a lazy expression dataset in personal space.

A dataset with the given name is created anew (or overwritten if already existing).

Parameters:

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

• expression (str) – The expression to be evaluated. It must result in a lazy expression.

• operands (dict) – A mapping of the variables used in the expression to the dataset paths that they refer to.

• urlbase (str) – The base of URLs of the subscriber to query. Default is caterva2.sub_urlbase_default.

• auth_cookie (str) – An HTTP cookie for authorizing access. This must be specified unless it was already specified inside a :py_obj:`caterva2.c2context`.

Returns:

The 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=urlbase, auth_cookie=auth_cookie)
>>> cat2.lazyexpr('example-expr', 'a + a', {'a': path}, urlbase=urlbase, auth_cookie=auth_cookie)
PosixPath('@personal/example-expr.b2nd')
>>> 'example-expr.b2nd' in cat2.get_list('@personal', urlbase, auth_cookie)
True