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A collection of utility functions and classes. Many (but not all) from the Python Cookbook – hence the name cbook

class matplotlib.cbook.Bunch(**kwds)

Often we want to just collect a bunch of stuff together, naming each item of the bunch; a dictionary’s OK for that, but a small do- nothing class is even handier, and prettier to use. Whenever you want to group a few variables:

>>> point = Bunch(datum=2, squared=4, coord=12)
>>> point.datum

By: Alex Martelli
class matplotlib.cbook.CallbackRegistry(*args)

Handle registering and disconnecting for a set of signals and callbacks:

>>> def oneat(x):
...    print 'eat', x
>>> def ondrink(x):
...    print 'drink', x
>>> from matplotlib.cbook import CallbackRegistry
>>> callbacks = CallbackRegistry()
>>> id_eat = callbacks.connect('eat', oneat)
>>> id_drink = callbacks.connect('drink', ondrink)
>>> callbacks.process('drink', 123)
drink 123
>>> callbacks.process('eat', 456)
eat 456
>>> callbacks.process('be merry', 456) # nothing will be called
>>> callbacks.disconnect(id_eat)
>>> callbacks.process('eat', 456)      # nothing will be called

In practice, one should always disconnect all callbacks when they are no longer needed to avoid dangling references (and thus memory leaks). However, real code in matplotlib rarely does so, and due to its design, it is rather difficult to place this kind of code. To get around this, and prevent this class of memory leaks, we instead store weak references to bound methods only, so when the destination object needs to die, the CallbackRegistry won’t keep it alive. The Python stdlib weakref module can not create weak references to bound methods directly, so we need to create a proxy object to handle weak references to bound methods (or regular free functions). This technique was shared by Peter Parente on his “Mindtrove” blog.

connect(s, func)

register func to be called when a signal s is generated func will be called


disconnect the callback registered with callback id cid

process(s, *args, **kwargs)

process signal s. All of the functions registered to receive callbacks on s will be called with *args and **kwargs

class matplotlib.cbook.GetRealpathAndStat
class matplotlib.cbook.Grouper(init=[])

Bases: object

This class provides a lightweight way to group arbitrary objects together into disjoint sets when a full-blown graph data structure would be overkill.

Objects can be joined using join(), tested for connectedness using joined(), and all disjoint sets can be retreived by using the object as an iterator.

The objects being joined must be hashable and weak-referenceable.

For example:

>>> from matplotlib.cbook import Grouper
>>> class Foo(object):
...     def __init__(self, s):
...         self.s = s
...     def __repr__(self):
...         return self.s
>>> a, b, c, d, e, f = [Foo(x) for x in 'abcdef']
>>> grp = Grouper()
>>> grp.join(a, b)
>>> grp.join(b, c)
>>> grp.join(d, e)
>>> sorted(map(tuple, grp))
[(d, e), (a, b, c)]
>>> grp.joined(a, b)
>>> grp.joined(a, c)
>>> grp.joined(a, d)

Clean dead weak references from the dictionary


Returns all of the items joined with a, including itself.

join(a, *args)

Join given arguments into the same set. Accepts one or more arguments.

joined(a, b)

Returns True if a and b are members of the same set.

class matplotlib.cbook.Idle(func)

Bases: matplotlib.cbook.Scheduler

Schedule callbacks when scheduler is idle

waittime = 0.05
class matplotlib.cbook.MemoryMonitor(nmax=20000)
plot(i0=0, isub=1, fig=None)
xy(i0=0, isub=1)
class matplotlib.cbook.Null(*args, **kwargs)

Null objects always and reliably “do nothing.”

class matplotlib.cbook.RingBuffer(size_max)

class that implements a not-yet-full buffer


append an element at the end of the buffer


Return a list of elements from the oldest to the newest.

class matplotlib.cbook.Scheduler

Bases: threading.Thread

Base class for timeout and idle scheduling

id = 0
idlelock = <thread.lock object at 0x1230650>
class matplotlib.cbook.Sorter

Sort by attribute or item

Example usage:

sort = Sorter()

list = [(1, 2), (4, 8), (0, 3)]
dict = [{'a': 3, 'b': 4}, {'a': 5, 'b': 2}, {'a': 0, 'b': 0},
        {'a': 9, 'b': 9}]

sort(list)       # default sort
sort(list, 1)    # sort by index 1
sort(dict, 'a')  # sort a list of dicts by key 'a'
byAttribute(data, attributename, inplace=1)
byItem(data, itemindex=None, inplace=1)
sort(data, itemindex=None, inplace=1)
class matplotlib.cbook.Stack(default=None)

Bases: object

Implement a stack where elements can be pushed on and you can move back and forth. But no pop. Should mimic home / back / forward in a browser


move the position back and return the current element


raise o to the top of the stack and return o. o must be in the stack


empty the stack


move the position forward and return the current element


push the first element onto the top of the stack


push object onto stack at current position - all elements occurring later than the current position are discarded


remove element o from the stack

class matplotlib.cbook.Timeout(wait, func)

Bases: matplotlib.cbook.Scheduler

Schedule recurring events with a wait time in seconds

class matplotlib.cbook.Xlator

Bases: dict

All-in-one multiple-string-substitution class

Example usage:

text = "Larry Wall is the creator of Perl"
adict = {
"Larry Wall" : "Guido van Rossum",
"creator" : "Benevolent Dictator for Life",
"Perl" : "Python",

print multiple_replace(adict, text)

xlat = Xlator(adict)
print xlat.xlat(text)

Translate text, returns the modified text.

matplotlib.cbook.align_iterators(func, *iterables)

This generator takes a bunch of iterables that are ordered by func It sends out ordered tuples:

(func(row), [rows from all iterators matching func(row)])

It is used by matplotlib.mlab.recs_join() to join record arrays


Return True if all elements of seq compare equal. If seq is 0 or 1 length, return True


return all possible pairs in sequence x

Condensed by Alex Martelli from this thread on c.l.python


Return True if all elements of seq evaluate to True. If seq is empty, return False.

class matplotlib.cbook.converter(missing='Null', missingval=None)

Base class for handling string -> python type with support for missing values


Remove excess indentation from docstring s.

Discards any leading blank lines, then removes up to n whitespace characters from each line, where n is the number of leading whitespace characters in the first line. It differs from textwrap.dedent in its deletion of leading blank lines and its use of the first non-blank line to determine the indentation.

It is also faster in most cases.


Find all masked and/or non-finite points in a set of arguments, and return the arguments with only the unmasked points remaining.

Arguments can be in any of 5 categories:

  1. 1-D masked arrays
  2. 1-D ndarrays
  3. ndarrays with more than one dimension
  4. other non-string iterables
  5. anything else

The first argument must be in one of the first four categories; any argument with a length differing from that of the first argument (and hence anything in category 5) then will be passed through unchanged.

Masks are obtained from all arguments of the correct length in categories 1, 2, and 4; a point is bad if masked in a masked array or if it is a nan or inf. No attempt is made to extract a mask from categories 2, 3, and 4 if np.isfinite() does not yield a Boolean array.

All input arguments that are not passed unchanged are returned as ndarrays after removing the points or rows corresponding to masks in any of the arguments.

A vastly simpler version of this function was originally written as a helper for Axes.scatter().

matplotlib.cbook.dict_delall(d, keys)

delete all of the keys from the dict d


This function has been moved to matplotlib.mlab – please import it from there

matplotlib.cbook.finddir(o, match, case=False)

return all attributes of o which match string in match. if case is True require an exact case match.

matplotlib.cbook.flatten(seq, scalarp=<function is_scalar_or_string at 0x180fb90>)

Returns a generator of flattened nested containers

For example:

>>> from matplotlib.cbook import flatten
>>> l = (('John', ['Hunter']), (1, 23), [[([42, (5, 23)], )]])
>>> print list(flatten(l))
['John', 'Hunter', 1, 23, 42, 5, 23]

By: Composite of Holger Krekel and Luther Blissett From: and Recipe 1.12 in cookbook


Recurse all the files and dirs in args ignoring symbolic links and return the files as a list of strings

matplotlib.cbook.get_sample_data(fname, asfileobj=True)

Return a sample data file. fname is a path relative to the mpl-data/sample_data directory. If asfileobj is True return a file object, otherwise just a file path.

Set the rc parameter to the directory where we should look, if sample_data files are stored in a location different than default (which is ‘mpl-data/sample_data` at the same level of ‘matplotlib` Python module files).

If the filename ends in .gz, the file is implicitly ungzipped.

matplotlib.cbook.get_split_ind(seq, N)

seq is a list of words. Return the index into seq such that:

len(' '.join(seq[:ind])<=N



This function has been moved to matplotlib.mlab – please import it from there


return true if obj looks like a number


return true if obj is not string like and is not iterable


Return whether the given object is a scalar or string like.


Returns true if obj is iterable and contains strings


Return True if obj looks like a string


return true if obj looks like a file object with a write method

matplotlib.cbook.issubclass_safe(x, klass)

return issubclass(x, klass) and return False on a TypeError


return true if obj is iterable

matplotlib.cbook.less_simple_linear_interpolation(x, y, xi, extrap=False)

This function has been moved to matplotlib.mlab – please import it from there

matplotlib.cbook.listFiles(root, patterns='*', recurse=1, return_folders=0)

Recursively list files

from Parmar and Martelli in the Python Cookbook

class matplotlib.cbook.maxdict(maxsize)

Bases: dict

A dictionary with a maximum size; this doesn’t override all the relevant methods to contrain size, just setitem, so use with caution

matplotlib.cbook.mkdirs(newdir, mode=511)

make directory newdir recursively, and set mode. Equivalent to

> mkdir -p NEWDIR

Return True if one element of seq is True. It seq is empty, return False.


This function has been moved to matplotlib.mlab – please import it from there

matplotlib.cbook.pieces(seq, num=2)

Break up the seq into num tuples


empty a list

matplotlib.cbook.print_cycles(objects, outstream=<open file '<stdout>', mode 'w' at 0x7f07a97501e0>, show_progress=False)
A list of objects to find cycles in. It is often useful to pass in gc.garbage to find the cycles that are preventing some objects from being garbage collected.
The stream for output.
If True, print the number of objects reached as they are found.
matplotlib.cbook.quad2cubic(q0x, q0y, q1x, q1y, q2x, q2y)

This function has been moved to matplotlib.mlab – please import it from there


return the memory consumed by process

matplotlib.cbook.restrict_dict(d, keys)

Return a dictionary that contains those keys that appear in both d and keys, with values from d.


reverse the dictionary – may lose data if values are not unique!


make sure args are equal len before zipping

class matplotlib.cbook.silent_list(type, seq=None)

Bases: list

override repr when returning a list of matplotlib artists to prevent long, meaningless output. This is meant to be used for a homogeneous list of a given type

matplotlib.cbook.simple_linear_interpolation(a, steps)
matplotlib.cbook.soundex(name, len=4)

soundex module conforming to Odell-Russell algorithm


remove latex formatting from mathtext

matplotlib.cbook.to_filehandle(fname, flag='rU', return_opened=False)

fname can be a filename or a file handle. Support for gzipped files is automatic, if the filename ends in .gz. flag is a read/write flag for file()

class matplotlib.cbook.todate(fmt='%Y-%m-%d', missing='Null', missingval=None)

Bases: matplotlib.cbook.converter

convert to a date or None

use a time.strptime() format string for conversion

class matplotlib.cbook.todatetime(fmt='%Y-%m-%d', missing='Null', missingval=None)

Bases: matplotlib.cbook.converter

convert to a datetime or None

use a time.strptime() format string for conversion

class matplotlib.cbook.tofloat(missing='Null', missingval=None)

Bases: matplotlib.cbook.converter

convert to a float or None

class matplotlib.cbook.toint(missing='Null', missingval=None)

Bases: matplotlib.cbook.converter

convert to an int or None

class matplotlib.cbook.tostr(missing='Null', missingval='')

Bases: matplotlib.cbook.converter

convert to string or None


Return a list of unique elements of x

matplotlib.cbook.unmasked_index_ranges(mask, compressed=True)

Find index ranges where mask is False.

mask will be flattened if it is not already 1-D.

Returns Nx2 numpy.ndarray with each row the start and stop indices for slices of the compressed numpy.ndarray corresponding to each of N uninterrupted runs of unmasked values. If optional argument compressed is False, it returns the start and stop indices into the original numpy.ndarray, not the compressed numpy.ndarray. Returns None if there are no unmasked values.


y = ma.array(np.arange(5), mask = [0,0,1,0,0])
ii = unmasked_index_ranges(ma.getmaskarray(y))
# returns array [[0,2,] [2,4,]]

# returns array [3,4,]

ii = unmasked_index_ranges(ma.getmaskarray(y), compressed=False)
# returns array [[0, 2], [3, 5]]

# returns array [3,4,]

Prior to the transforms refactoring, this was used to support masked arrays in Line2D.

matplotlib.cbook.vector_lengths(X, P=2.0, axis=None)

This function has been moved to matplotlib.mlab – please import it from there

matplotlib.cbook.wrap(prefix, text, cols)

wrap text with prefix at length cols