class StringConverter: (source)
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.
Attributes
- func : function
- Function used for the conversion.
- default : any
- Default value to return when the input corresponds to a missing value.
- type : type
- Type of the output.
- _status : int
- Integer representing the order of the conversion.
- _mapper : sequence of tuples
- Sequence of tuples (dtype, function, default value) to evaluate in order.
- _locked : bool
- Holds
locked
parameter.
Parameters
- dtype_or_func : {None, dtype, function}, optional
- If a
dtype
, specifies the input data type, used to define a basic function and a default value for missing data. For example, whendtype
is float, thefunc
attribute is set tofloat
and the default value tonp.nan
. If a function, this function is used to convert a string to another object. In this case, it is recommended to give an associated default value as input. - default : any, optional
- Value to return by default, that is, when the string to be
converted is flagged as missing. If not given,
StringConverter
tries to supply a reasonable default value. - missing_values : {None, sequence of str}, optional
- None or sequence of strings indicating a missing value. If None then missing values are indicated by empty entries. The default is None.
- locked : bool, optional
- Whether the StringConverter should be locked to prevent automatic upgrade or not. Default is False.
Class Method | upgrade |
Upgrade the mapper of a StringConverter by adding a new function and its corresponding default. |
Method | __call__ |
Undocumented |
Method | __init__ |
Undocumented |
Method | iterupgrade |
Undocumented |
Method | update |
Set StringConverter attributes directly. |
Method | upgrade |
Find the best converter for a given string, and return the result. |
Instance Variable | default |
Undocumented |
Instance Variable | func |
Undocumented |
Instance Variable | missing |
Undocumented |
Instance Variable | type |
Undocumented |
Class Method | _dtypeortype |
Returns dtype for datetime64 and type of dtype otherwise. |
Class Method | _find |
Undocumented |
Class Method | _getdtype |
Returns the dtype of the input variable. |
Class Method | _getsubdtype |
Returns the type of the dtype of the input variable. |
Method | _do |
Undocumented |
Method | _loose |
Undocumented |
Method | _strict |
Undocumented |
Class Variable | _mapper |
Undocumented |
Instance Variable | _callingfunction |
Undocumented |
Instance Variable | _checked |
Undocumented |
Instance Variable | _initial |
Undocumented |
Instance Variable | _locked |
Undocumented |
Instance Variable | _status |
Undocumented |
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 = dateutil.parser.parse >>> defaultdate = datetime.date(2000, 1, 1) >>> StringConverter.upgrade_mapper(dateparser, default=defaultdate)
Set StringConverter attributes directly.
Parameters
- func : function
- Conversion function.
- default : any, optional
- Value to return by default, that is, when the string to be
converted is flagged as missing. If not given,
StringConverter
tries to supply a reasonable default value. - testing_value : str, optional
- A string representing a standard input value of the converter. This string is used to help defining a reasonable default value.
- missing_values : {sequence of str, None}, optional
- Sequence of strings indicating a missing value. If None, then
the existing
missing_values
are cleared. The default is''
. - locked : bool, optional
- Whether the StringConverter should be locked to prevent automatic upgrade or not. Default is False.
Notes
update
takes the same parameters as the constructor of
StringConverter
, except that func
does not accept a dtype
whereas dtype_or_func
in the constructor does.
Find the best converter for a given string, and return the result.
The supplied string value
is converted by testing different
converters in order. First the func
method of the
StringConverter
instance is tried, if this fails other available
converters are tried. The order in which these other converters
are tried is determined by the _status
attribute of the instance.
Parameters
- value : str
- The string to convert.
Returns
- out : any
- The result of converting
value
with the appropriate converter.