Coverage for local/lib/python2.7/site-packages/sage/geometry/polyhedron/misc.py : 83%

r""" 

Miscellaneous helper functions 

""" 

######################################################################## 

# Copyright (C) 2008 Marshall Hampton <hamptonio@gmail.com> 

# Copyright (C) 2011 Volker Braun <vbraun.name@gmail.com> 

# 

# Distributed under the terms of the GNU General Public License (GPL) 

# 

# http://www.gnu.org/licenses/ 

######################################################################## 

######################################################################### 

def _to_space_separated_string(l): 

""" 

Converts a container to a space-separated string. 

INPUT: 

- ``l`` -- anything iterable. 

OUTPUT: 

String. 

EXAMPLES:: 

sage: import sage.geometry.polyhedron.misc as P 

sage: P._to_space_separated_string([2,3]) 

'2 3' 

""" 

s = ''; 

for x in l: 

if len(s)>0: s += ' ' 

s += repr(x) 

return s 

######################################################################### 

def _set_to_None_if_empty(x): 

""" 

Helper function to clean up arguments: Returns None if x==None or 

x is an empty container. 

EXAMPLES:: 

sage: import sage.geometry.polyhedron.misc as P 

sage: None == P._set_to_None_if_empty([]) 

True 

sage: P._set_to_None_if_empty([1]) 

[1] 

""" 

if x is None: return x 

x = list(x) 

if len(x)==0: return None 

return x 

######################################################################### 

def _make_listlist(x): 

""" 

Helper function to clean up arguments. 

INPUT: 

- ``x`` -- ``None`` or an iterable of iterables. 

OUTPUT: 

A list of lists. 

EXAMPLES:: 

sage: import sage.geometry.polyhedron.misc as P 

sage: [] == P._make_listlist(tuple()) 

True 

sage: [] == P._make_listlist(None) 

True 

sage: P._make_listlist([(1,2),[3,4]]) 

[[1, 2], [3, 4]] 

""" 

if x is None: return [] 

return [list(y) for y in x] 

######################################################################### 

def _common_length_of(l1, l2=None, l3=None): 

""" 

The arguments are containers or ``None``. The function applies 

``len()`` to each element, and returns the common length. If the 

length differs, ``ValueError`` is raised. Used to check arguments. 

OUTPUT: 

A tuple (number of entries, common length of the entries) 

EXAMPLES:: 

sage: import sage.geometry.polyhedron.misc as P 

sage: P._common_length_of([[1,2,3],[1,3,34]]) 

(2, 3) 

""" 

args = []; 

if l1 is not None: args.append(l1) 

if l2 is not None: args.append(l2) 

if l3 is not None: args.append(l3) 

length = None 

num = 0 

for l in args: 

for i in l: 

num += 1 

length_i = len(i) 

if length is not None and length_i != length: 

raise ValueError("Argument lengths differ!") 

length = length_i 

return num, length