numpy.ma.mrecords

module documentation

(source)

numpy.ma..mrecords

Defines the equivalent of numpy.recarrays for masked arrays, where fields can be accessed as attributes. Note that numpy.ma.MaskedArray already supports structured datatypes and the masking of individual fields.

Class	`MaskedRecords`	No summary
Function	`addfield`	Adds a new field to the masked record array
Function	`fromarrays`	Creates a mrecarray from a (flat) list of masked arrays.
Function	`fromrecords`	Creates a MaskedRecords from a list of records.
Function	`fromtextfile`	Creates a mrecarray from data stored in the file `filename`.
Function	`openfile`	Opens the file handle of file `fname`.
Variable	`reserved_fields`	Undocumented
Function	`_checknames`	Checks that field names `descr` are not reserved keywords.
Function	`_get_fieldmask`	Undocumented
Function	`_guessvartypes`	Tries to guess the dtypes of the str_ ndarray `arr`.
Function	`_mrreconstruct`	Build a new MaskedArray from the information stored in a pickle.

def addfield(mrecord, newfield, newfieldname=None): (source) ¶

Adds a new field to the masked record array

Uses newfield as data and newfieldname as name. If newfieldname is None, the new field name is set to 'fi', where i is the number of existing fields.

def fromarrays(arraylist, dtype=None, shape=None, formats=None, names=None, titles=None, aligned=False, byteorder=None, fill_value=None): (source) ¶

Creates a mrecarray from a (flat) list of masked arrays.

Notes

Lists of tuples should be preferred over lists of lists for faster processing.

Parameters
arraylist:`sequence`	A list of (masked) arrays. Each element of the sequence is first converted to a masked array if needed. If a 2D array is passed as argument, it is processed line by line
dtype:{None, dtype}, optional	Data type descriptor.
shape:{None, integer}, optional	Number of records. If None, shape is defined from the shape of the first array in the list.
formats:{None, sequence}, optional	Sequence of formats for each individual field. If None, the formats will be autodetected by inspecting the fields and selecting the highest dtype possible.
names:{None, sequence}, optional	Sequence of the names of each field.
titles	Undocumented
aligned	Undocumented
byteorder	Undocumented
fill_value:{None, sequence}, optional	Sequence of data to be used as filling values.

def fromrecords(reclist, dtype=None, shape=None, formats=None, names=None, titles=None, aligned=False, byteorder=None, fill_value=None, mask=nomask): (source) ¶

Creates a MaskedRecords from a list of records.

Notes

Lists of tuples should be preferred over lists of lists for faster processing.

Parameters
reclist:`sequence`	A list of records. Each element of the sequence is first converted to a masked array if needed. If a 2D array is passed as argument, it is processed line by line
dtype:{None, dtype}, optional	Data type descriptor.
shape:{None, int}, optional	Number of records. If None, `shape` is defined from the shape of the first array in the list.
formats:{None, sequence}, optional	Sequence of formats for each individual field. If None, the formats will be autodetected by inspecting the fields and selecting the highest dtype possible.
names:{None, sequence}, optional	Sequence of the names of each field.
titles	Undocumented
aligned	Undocumented
byteorder	Undocumented
fill_value:{None, sequence}, optional	Sequence of data to be used as filling values.
mask:{nomask, sequence}, `optional.`	External mask to apply on the data.

def fromtextfile(fname, delimiter=None, commentchar='#', missingchar='', varnames=None, vartypes=None, *, delimitor=np._NoValue): (source) ¶

Creates a mrecarray from data stored in the file filename.

Ultra simple: the varnames are in the header, one line

Parameters
fname:{file name/handle}	Handle of an opened file.
delimiter:{None, string}, optional	Alphanumeric character used to separate columns in the file. If None, any (group of) white spacestring(s) will be used.
commentchar:{'#', string}, optional	Alphanumeric character used to mark the start of a comment.
missingchar:{'', string}, optional	String indicating missing data, and used to create the masks.
varnames:{None, sequence}, optional	Sequence of the variable names. If None, a list will be created from the first non empty line of the file.
vartypes:{None, sequence}, optional	Sequence of the variables dtypes. If None, it will be estimated from the first non-commented line.
delimitor	Undocumented

def openfile(fname): (source) ¶

Opens the file handle of file fname.

reserved_fields: list[str] = (source) ¶

Undocumented

def _checknames(descr, names=None): (source) ¶

Checks that field names descr are not reserved keywords.

If this is the case, a default 'f%i' is substituted. If the argument names is not None, updates the field names to valid names.

def _get_fieldmask(self): (source) ¶

Undocumented

def _guessvartypes(arr): (source) ¶

Tries to guess the dtypes of the str_ ndarray arr.

Guesses by testing element-wise conversion. Returns a list of dtypes. The array is first converted to ndarray. If the array is 2D, the test is performed on the first line. An exception is raised if the file is 3D or more.

def _mrreconstruct(subtype, baseclass, baseshape, basetype): (source) ¶

Build a new MaskedArray from the information stored in a pickle.