U
|
¬ý°d:8 ã @ s d Z ddlmZ ddlZddlmZ ddlZddlmZ ddl m
|
Z
|
ddl m Z ddl mZ dd lmZmZ dd
|
lmZ dd lmZ dd lmZ dd lmZ er¬ddlmZ dddddZ ddddZ dd Z dd Z ddd d Z dd dd d d!Z!d*d%ddd d&d'd(d)Z"dS )+z
|
Top level ``eval`` module.
|
é )Ú annotationsN)Ú TYPE_CHECKING)Úfind_stack_level)Úvalidate_bool_kwarg©Úis_extension_array_dtype)ÚENGINES)ÚPARSERSÚExpr)Útokenize_string)Ú ensure_scope)ÚNDFrame)Ú pprint_thing)ÚBinOpz
|
str | NoneÚstr)ÚengineÚreturnc C sl ddl m} ddlm} | dkr,|r(dnd} | tkrTtt ¡ }td| d| | dkrh|shtd | S )
|
a?
|
Make sure a valid engine is passed.
|
|
Parameters
|
----------
|
engine : str
|
String to validate.
|
|
Raises
|
------
|
KeyError
|
* If an invalid engine is passed.
|
ImportError
|
* If numexpr was requested but doesn't exist.
|
|
Returns
|
-------
|
str
|
Engine name.
|
r )ÚNUMEXPR_INSTALLED)Ú USE_NUMEXPRNÚnumexprÚpythonzInvalid engine 'z ' passed, valid engines are z~'numexpr' is not installed or an unsupported version. Cannot use engine='numexpr' for query/eval if 'numexpr' is not installed) Z pandas.core.computation.checkr Z#pandas.core.computation.expressionsr r ÚlistÚkeysÚKeyErrorÚ ImportError)r r r Z valid_engines© r úSd:\z\workplace\vscode\pyvenv\venv\Lib\site-packages\pandas/core/computation/eval.pyÚ _check_engine s ÿ ÿr ©Úparserc C s$ | t kr td| dt ¡ dS )z¨
|
Make sure a valid parser is passed.
|
|
Parameters
|
----------
|
parser : str
|
|
Raises
|
------
|
KeyError
|
* If an invalid parser is passed
|
zInvalid parser 'z ' passed, valid parsers are N)r r r r r r r Ú _check_parserK s ÿr c C s: | d k r6| D ](}t |ds t|j}td| dq d S )NÚ __getitem__zResolver of type 'z+' does not implement the __getitem__ method)ÚhasattrÚtypeÚ__name__Ú TypeError)Ú resolversÚresolverÚnamer r r Ú_check_resolvers^ s
|
|
|
ÿr) c C s | s t ddS )zæ
|
Make sure an expression is not an empty string
|
|
Parameters
|
----------
|
expr : object
|
An object that can be converted to a string
|
|
Raises
|
------
|
ValueError
|
* If expr is an empty string
|
z expr cannot be an empty stringN)Ú
|
ValueError)Úexprr r r Ú_check_expressioni s r, )r c C s t | }t| |S )a&
|
Convert an object to an expression.
|
|
This function converts an object to an expression (a unicode string) and
|
checks to make sure it isn't empty after conversion. This is used to
|
convert operators to their string representation for recursive calls to
|
:func:`~pandas.eval`.
|
|
Parameters
|
----------
|
expr : object
|
The object to be converted to a string.
|
|
Returns
|
-------
|
str
|
The string representation of an object.
|
|
Raises
|
------
|
ValueError
|
* If the expression is empty.
|
)r r, )r+ Úsr r r Ú_convert_expression{ s r. Úint)r+ Ú stack_levelr c C sZ |dk}|dk}|rd}n|r"d}|s*|rVt | D ]"\}}|tjkr2|dkr2t|q2d S )Nr Úpandasz5The '@' prefix is only supported by the pandas parserzuThe '@' prefix is not allowed in top-level eval calls.
|
please refer to your variables by name without the '@' prefix.ú@)r ÚtokenizeÚOPÚ SyntaxError)r+ r0 r Zat_top_of_stackZnot_pandas_parserÚmsgÚtoknumÚtokvalr r r Ú_check_for_locals s ÿr9 r1 r Fz str | BinOpÚbool)r+ r r ÚlevelÚinplacec C s® t |d}t| tr0t| dd | ¡ D } n| g} t| dk}
|
|
|
rV|dkrVtdt|}t| t | d} d} d} | D ]} t
|
| } t | || t |d ||||d }t | |||d
|
}|d krt|jjst|jd ddk rtd d |jjD rtjdtt d d}t| }||}| ¡ } |jdkrX|
|
rJtd|rXtd|j}|jdk r~|dk r~d} |sÀ| rÀz|j ¡ }W n. t k
|
r¼ } ztd|W 5 d}~X Y nX n|j}zJtj dd4 |rüt|t rü| |j dd
|f< n| ||< W 5 Q R X W n2 t!t"fk
|
rB } ztd|W 5 d}~X Y nX |sV|| if}n2|D ] }||krZ| ||< qqZ||| if7 }d} d} q~|dkrª| r¦|S | S dS )a'
|
Evaluate a Python expression as a string using various backends.
|
|
The following arithmetic operations are supported: ``+``, ``-``, ``*``,
|
``/``, ``**``, ``%``, ``//`` (python engine only) along with the following
|
boolean operations: ``|`` (or), ``&`` (and), and ``~`` (not).
|
Additionally, the ``'pandas'`` parser allows the use of :keyword:`and`,
|
:keyword:`or`, and :keyword:`not` with the same semantics as the
|
corresponding bitwise operators. :class:`~pandas.Series` and
|
:class:`~pandas.DataFrame` objects are supported and behave as they would
|
with plain ol' Python evaluation.
|
|
Parameters
|
----------
|
expr : str
|
The expression to evaluate. This string cannot contain any Python
|
`statements
|
<https://docs.python.org/3/reference/simple_stmts.html#simple-statements>`__,
|
only Python `expressions
|
<https://docs.python.org/3/reference/simple_stmts.html#expression-statements>`__.
|
parser : {'pandas', 'python'}, default 'pandas'
|
The parser to use to construct the syntax tree from the expression. The
|
default of ``'pandas'`` parses code slightly different than standard
|
Python. Alternatively, you can parse an expression using the
|
``'python'`` parser to retain strict Python semantics. See the
|
:ref:`enhancing performance <enhancingperf.eval>` documentation for
|
more details.
|
engine : {'python', 'numexpr'}, default 'numexpr'
|
|
The engine used to evaluate the expression. Supported engines are
|
|
- None : tries to use ``numexpr``, falls back to ``python``
|
- ``'numexpr'`` : This default engine evaluates pandas objects using
|
numexpr for large speed ups in complex expressions with large frames.
|
- ``'python'`` : Performs operations as if you had ``eval``'d in top
|
level python. This engine is generally not that useful.
|
|
More backends may be available in the future.
|
local_dict : dict or None, optional
|
A dictionary of local variables, taken from locals() by default.
|
global_dict : dict or None, optional
|
A dictionary of global variables, taken from globals() by default.
|
resolvers : list of dict-like or None, optional
|
A list of objects implementing the ``__getitem__`` special method that
|
you can use to inject an additional collection of namespaces to use for
|
variable lookup. For example, this is used in the
|
:meth:`~DataFrame.query` method to inject the
|
``DataFrame.index`` and ``DataFrame.columns``
|
variables that refer to their respective :class:`~pandas.DataFrame`
|
instance attributes.
|
level : int, optional
|
The number of prior stack frames to traverse and add to the current
|
scope. Most users will **not** need to change this parameter.
|
target : object, optional, default None
|
This is the target object for assignment. It is used when there is
|
variable assignment in the expression. If so, then `target` must
|
support item assignment with string keys, and if a copy is being
|
returned, it must also support `.copy()`.
|
inplace : bool, default False
|
If `target` is provided, and the expression mutates `target`, whether
|
to modify `target` inplace. Otherwise, return a copy of `target` with
|
the mutation.
|
|
Returns
|
-------
|
ndarray, numeric scalar, DataFrame, Series, or None
|
The completion value of evaluating the given code or None if ``inplace=True``.
|
|
Raises
|
------
|
ValueError
|
There are many instances where such an error can be raised:
|
|
- `target=None`, but the expression is multiline.
|
- The expression is multiline, but not all them have item assignment.
|
An example of such an arrangement is this:
|
|
a = b + 1
|
a + 2
|
|
Here, there are expressions on different lines, making it multiline,
|
but the last line has no variable assigned to the output of `a + 2`.
|
- `inplace=True`, but the expression is missing item assignment.
|
- Item assignment is provided, but the `target` does not support
|
string item assignment.
|
- Item assignment is provided and `inplace=False`, but the `target`
|
does not support the `.copy()` method
|
|
See Also
|
--------
|
DataFrame.query : Evaluates a boolean expression to query the columns
|
of a frame.
|
DataFrame.eval : Evaluate a string describing operations on
|
DataFrame columns.
|
|
Notes
|
-----
|
The ``dtype`` of any objects involved in an arithmetic ``%`` operation are
|
recursively cast to ``float64``.
|
|
See the :ref:`enhancing performance <enhancingperf.eval>` documentation for
|
more details.
|
|
Examples
|
--------
|
>>> df = pd.DataFrame({"animal": ["dog", "pig"], "age": [10, 20]})
|
>>> df
|
animal age
|
0 dog 10
|
1 pig 20
|
|
We can add a new column using ``pd.eval``:
|
|
>>> pd.eval("double_age = df.age * 2", target=df)
|
animal age double_age
|
0 dog 10 20
|
1 pig 20 40
|
r< c S s g | ]}| ¡ d kr| ¡ qS )Ú )Ústrip)Ú.0Úer r r Ú
|
<listcomp>0 s zeval.<locals>.<listcomp>é NzPmulti-line expressions are only valid in the context of data, use DataFrame.evalTF)Ú global_dictÚ
|
local_dictr& Útarget)r r Úenvr Ú operand_typesc s s | ]}t |V qd S )Nr )r? Úelemr r r Ú <genexpr>U s ÿzeval.<locals>.<genexpr>zEngine has switched to 'python' because numexpr does not support extension array dtypes. Please set your engine to python manually.)Ú
|
stacklevelr zNMulti-line expressions are only valid if all expressions contain an assignmentz0Cannot operate inplace if there is no assignmentz"Cannot return a copy of the target)Úrecordz)Cannot assign expression output to target)#r Ú
|
isinstancer r, Ú
|
splitlinesÚlenr* r r r) r. r9 r r
|
r ZtermsÚ return_typeÚgetattrÚanyrG ÚwarningsÚwarnÚRuntimeWarningr r ÚevaluateÚassignerrE ÚcopyÚAttributeErrorÚcatch_warningsr Úlocr% Ú
|
IndexError)r+ r r rD rC r& r; rE r< ÚexprsZ
|
multi_lineÚretZ
|
first_exprZtarget_modifiedrF Z parsed_exprZengZeng_instrV Úerrr' r r r Úevalª s
|
|
ÿ
|
û
|
|
ÿþþýü ÿ
|
|
|
r_ )r1 NNNr r NF)#Ú__doc__Ú
|
__future__r r3 Útypingr rR Zpandas.util._exceptionsr Zpandas.util._validatorsr Zpandas.core.dtypes.commonr Z pandas.core.computation.enginesr Z pandas.core.computation.exprr r
|
Z pandas.core.computation.parsingr Z pandas.core.computation.scoper Zpandas.core.genericr Zpandas.io.formats.printingr Zpandas.core.computation.opsr r r r) r, r. r9 r_ r r r r Ú<module> s< - ÷
|
