Package pygeodesy :: Module basics
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Module basics

Some, basic definitions, functions and dependencies.

Use env variable PYGEODESY_XPACKAGES to avoid import of dependencies geographiclib, numpy and/or scipy. Set PYGEODESY_XPACKAGES to a comma-separated list of package names to be excluded from import.


Version: 22.09.16

Functions
 
str2ub(x)
NOP, pass thru.
 
ub2str(x)
NOP, pass thru.
 
clips(sb, limit=50, white='')
Clip a string to the given length limit.
 
copysign0(x, y)
Like math.copysign(x, y) except zero, unsigned.
 
copytype(x, y)
Return the value of x as type of y.
 
halfs2(str2)
Split a string in 2 halfs.
 
isbool(obj)
Check whether an object is boolean.
 
isclass(obj)
Return True if obj is a class or type.
 
iscomplex(obj)
Check whether an object is complex.
 
isfloat(obj)
Check whether an object is a float or float str.
 
isidentifier(obj)
Return True if obj is a valid Python identifier.
 
isint(obj, both=False)
Check for int type or an integer float value.
 
iskeyword(x, y)
y in x.
 
isodd(x)
Is x odd?
 
isscalar(obj)
Check for scalar types.
 
issequence(obj, *excls)
Check for sequence types.
 
isstr(obj)
Check for string types.
 
issubclassof(Sub, *Supers)
Check whether a class is a sub-class of some other class(es).
 
istuplist(obj, minum=0)
Check for tuple or list types and minumal length.
 
len2(items)
Make built-in function len work for generators, iterators, etc.
 
map1(fun1, *xs)
Apply each argument to a single-argument function and return a tuple of results.
 
map2(func, *xs)
Apply arguments to a function and return a tuple of results.
 
neg(x)
Negate x unless zero or NEG0.
 
neg_(*xs)
Negate all of xs with neg.
 
signBit(x)
Return signbit(x), like C++.
 
signOf(x)
Return sign of x as int.
 
splice(iterable, n=2, **fill)
Split an iterable into n slices.
 
unsigned0(x)
Return 0.0 unsigned.
Variables
  __all__ = _ALL_LAZY.basics
Function Details

clips (sb, limit=50, white='')

 

Clip a string to the given length limit.

Arguments:
  • sb - String (str or bytes).
  • limit - Length limit (int).
  • white - Optionally, replace all whitespace (str).
Returns:
The clipped or unclipped sb.

copysign0 (x, y)

 

Like math.copysign(x, y) except zero, unsigned.

Returns:
math.copysign(x, y) if x else type(x)(0).

copytype (x, y)

 

Return the value of x as type of y.

Returns:
type(y)(x).

halfs2 (str2)

 

Split a string in 2 halfs.

Arguments:
  • str2 - String to split (str).
Returns:
2-Tuple (_1st, _2nd) half (str).
Raises:
  • ValueError - Zero or odd len(str2).

isbool (obj)

 

Check whether an object is boolean.

Arguments:
  • obj - The object (any type).
Returns:
True if obj is boolean, False otherwise.

isclass (obj)

 

Return True if obj is a class or type.

See Also: Python's inspect.isclass.

iscomplex (obj)

 

Check whether an object is complex.

Arguments:
  • obj - The object (any type).
Returns:
True if obj is complex, False otherwise.

isfloat (obj)

 

Check whether an object is a float or float str.

Arguments:
  • obj - The object (any type).
Returns:
True if obj is a float, False otherwise.

isint (obj, both=False)

 

Check for int type or an integer float value.

Arguments:
  • obj - The object (any type).
  • both - If true, check float and Fsum type and value (bool).
Returns:
True if obj is int or integer float or Fsum, False otherwise.

Note: Both isint(True) and isint(False) return False (and no longer True).

isodd (x)

 

Is x odd?

Arguments:
  • x - Value (scalar).
Returns:
True if x is odd, False otherwise.

isscalar (obj)

 

Check for scalar types.

Arguments:
  • obj - The object (any type).
Returns:
True if obj is scalar, False otherwise.

issequence (obj, *excls)

 

Check for sequence types.

Arguments:
  • obj - The object (any type).
  • excls - Classes to exclude (type), all positional.
Returns:
True if obj is a sequence, False otherwise.

Note: Excluding tuple implies excluding namedtuple.

isstr (obj)

 

Check for string types.

Arguments:
  • obj - The object (any type).
Returns:
True if obj is str, False otherwise.

issubclassof (Sub, *Supers)

 

Check whether a class is a sub-class of some other class(es).

Arguments:
  • Sub - The sub-class (class).
  • Supers - One or more C(super) classes (class).
Returns:
True if Sub is a sub-class of any Supers, False if not (bool) or None if Sub is not a class or if no Supers are given or none of those are a class.

istuplist (obj, minum=0)

 

Check for tuple or list types and minumal length.

Arguments:
  • obj - The object (any type).
  • minum - Minimal len required C({int}).
Returns:
True if obj is tuple or list with len at least minum, False otherwise.

len2 (items)

 

Make built-in function len work for generators, iterators, etc. since those can only be started exactly once.

Arguments:
  • items - Generator, iterator, list, range, tuple, etc.
Returns:
2-Tuple (n, items) of the number of items (int) and the items (list or tuple).

map1 (fun1, *xs)

 

Apply each argument to a single-argument function and return a tuple of results.

Arguments:
  • fun1 - 1-Arg function to apply (callable).
  • xs - Arguments to apply (any positional).
Returns:
Function results (tuple).

map2 (func, *xs)

 

Apply arguments to a function and return a tuple of results.

Unlike Python 2's built-in map, Python 3+ map returns a map object, an iterator-like object which generates the results only once. Converting the map object to a tuple maintains the Python 2 behavior.

Arguments:
  • func - Function to apply (callable).
  • xs - Arguments to apply (list, tuple, ...).
Returns:
Function results (tuple).

neg (x)

 

Negate x unless zero or NEG0.

Returns:
-x if x else 0.0.

neg_ (*xs)

 

Negate all of xs with neg.

Returns:
A tuple(neg(x) for x in xs).

signBit (x)

 

Return signbit(x), like C++.

Returns:
True if x < 0 or NEG0 (bool).

signOf (x)

 

Return sign of x as int.

Returns:
-1, 0 or +1 (int).

splice (iterable, n=2, **fill)

 

Split an iterable into n slices.

Arguments:
  • iterable - Items to be spliced (list, tuple, ...).
  • n - Number of slices to generate (int).
  • fill - Optional fill value for missing items.
Returns:
A generator for each of n slices, iterable[i::n] for i=0..n.
Raises:
  • TypeError - Invalid n.

Note: Each generated slice is a tuple or a list, the latter only if the iterable is a list.

Example:

>>> from pygeodesy import splice
>>> a, b = splice(range(10))
>>> a, b
((0, 2, 4, 6, 8), (1, 3, 5, 7, 9))
>>> a, b, c = splice(range(10), n=3)
>>> a, b, c
((0, 3, 6, 9), (1, 4, 7), (2, 5, 8))
>>> a, b, c = splice(range(10), n=3, fill=-1)
>>> a, b, c
((0, 3, 6, 9), (1, 4, 7, -1), (2, 5, 8, -1))
>>> tuple(splice(list(range(9)), n=5))
([0, 5], [1, 6], [2, 7], [3, 8], [4])
>>> splice(range(9), n=1)
<generator object splice at 0x0...>

unsigned0 (x)

 

Return 0.0 unsigned.

Returns:
x if x else 0.0.