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- LineSplitter
- NameValidator
- StringConverter
class LineSplitter |
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Defines a function to split a string at a given delimiter or at given places.
Parameters
----------
comment : {'#', string}
Character used to mark the beginning of a comment.
delimiter : var, optional
If a string, character used to delimit consecutive fields.
If an integer or a sequence of integers, width(s) of each field.
autostrip : boolean, optional
Whether to strip each individual fields
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Methods defined here:
- __call__(self, line)
- __init__(self, delimiter=None, comments='#', autostrip=True)
- autostrip(self, method)
- Wrapper to strip each member of the output of `method`.
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class NameValidator |
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Validates a list of strings to use as field names.
The strings are stripped of any non alphanumeric character, and spaces
are replaced by `_`. If the optional input parameter `case_sensitive`
is False, the strings are set to upper case.
During instantiation, the user can define a list of names to exclude, as
well as a list of invalid characters. Names in the exclusion list
are appended a '_' character.
Once an instance has been created, it can be called with a list of names
and a list of valid names will be created.
The `__call__` method accepts an optional keyword, `default`, that sets
the default name in case of ambiguity. By default, `default = 'f'`, so
that names will default to `f0`, `f1`
Parameters
----------
excludelist : sequence, optional
A list of names to exclude. This list is appended to the default list
['return','file','print']. Excluded names are appended an underscore:
for example, `file` would become `file_`.
deletechars : string, optional
A string combining invalid characters that must be deleted from the names.
casesensitive : {True, False, 'upper', 'lower'}, optional
If True, field names are case_sensitive.
If False or 'upper', field names are converted to upper case.
If 'lower', field names are converted to lower case.
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Methods defined here:
- __call__(self, names, default='f')
- __init__(self, excludelist=None, deletechars=None, case_sensitive=None)
- validate(self, names, default='f')
Data and other attributes defined here:
- defaultdeletechars = set([' ', '!', '#', '$', '%', '&', ...])
- defaultexcludelist = ['return', 'file', 'print']
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class StringConverter |
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Factory class for function transforming a string into another object (int,
float).
After initialization, an instance can be called to transform a string
into another object. If the string is recognized as representing a missing
value, a default value is returned.
Parameters
----------
dtype_or_func : {None, dtype, function}, optional
Input data type, used to define a basic function and a default value
for missing data. For example, when `dtype` is float, the :attr:`func`
attribute is set to ``float`` and the default value to `np.nan`.
Alternatively, function used to convert a string to another object.
In that later case, it is recommended to give an associated default
value as input.
default : {None, var}, optional
Value to return by default, that is, when the string to be converted
is flagged as missing.
missing_values : {sequence}, optional
Sequence of strings indicating a missing value.
locked : {boolean}, optional
Whether the StringConverter should be locked to prevent automatic
upgrade or not.
Attributes
----------
func : function
Function used for the conversion
default : var
Default value to return when the input corresponds to a missing value.
type : type
Type of the output.
_status : integer
Integer representing the order of the conversion.
_mapper : sequence of tuples
Sequence of tuples (dtype, function, default value) to evaluate in order.
_locked : boolean
Whether the StringConverter is locked, thereby preventing automatic any
upgrade or not.
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Methods defined here:
- __call__(self, value)
- __init__(self, dtype_or_func=None, default=None, missing_values=None, locked=False)
- update(self, func, default=None, missing_values='', locked=False)
- Sets the :attr:`func` and :attr:`default` attributes directly.
Parameters
----------
func : function
Conversion function.
default : {var}, optional
Default value to return when a missing value is encountered.
missing_values : {var}, optional
Sequence of strings representing missing values.
locked : {False, True}, optional
Whether the status should be locked to prevent automatic upgrade.
- upgrade(self, value)
- Tries to find the best converter for `value`, by testing different
converters in order.
The order in which the converters are tested is read from the
:attr:`_status` attribute of the instance.
Class methods defined here:
- upgrade_mapper(cls, func, default=None) from __builtin__.classobj
- Upgrade the mapper of a StringConverter by adding a new function and its
corresponding default.
The input function (or sequence of functions) and its associated default
value (if any) is inserted in penultimate position of the mapper.
The corresponding type is estimated from the dtype of the default value.
Parameters
----------
func : var
Function, or sequence of functions
Examples
--------
>>> import dateutil.parser
>>> import datetime
>>> dateparser = datetutil.parser.parse
>>> defaultdate = datetime.date(2000, 1, 1)
>>> StringConverter.upgrade_mapper(dateparser, default=defaultdate)
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