Package pygeodesy :: Module basics
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Module basics

Basic constants, definitions and functions.


Version: 20.05.12

Classes
  property_RO
Functions
bool
isinf(x)
Check if float x is infinite (positive or negative).
bool
isnan(x)
Check if float x is not a number (NaN).
 
clips(bstr, limit=50, white='')
Clip a string to the given length limit.
 
halfs2(str2)
Split a string in 2 halfs.
 
isfinite(obj)
Check for Inf and NaN values.
 
isint(obj, both=False)
Check for int type or an integer float value.
 
isneg0(obj)
Check for NEG0, negative 0.0.
 
isscalar(obj)
Check for scalar types.
 
issequence(obj, *excluded)
Check for sequence types.
 
isstr(obj)
Check for string types.
 
issubclassof(Sub, Super)
Check whether a class is a sub-class of a super class.
 
len2(items)
Make built-in function len work for generators, iterators, etc.
 
map1(func, *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.
 
property_doc_(doc)
Decorator for a property with documentation.
Variables
  PI = 3.14159265359
  __all__ = _ALL_LAZY.basics
  EPS = 2.22044604925e-16
Epsilon (float) 2**-52?
  MANTIS = 53
Mantissa bits ≈53 (int)
  MAX = 1.79769313486e+308
Float max (float) ≈10**308, 2**1024?
  MIN = 2.22507385851e-308
System's float min (float)
  EPS_2 = 1.11022302463e-16
EPS / 2 ≈1.110223024625e-16 (float)
  EPS1 = 1.0
1 - EPS ≈0.9999999999999998 (float)
  EPS1_2 = 1.0
1 - EPS_2 ≈0.9999999999999999 (float)
  INF = inf
Infinity (float), see function isinf, isfinite
  NAN = nan
Not-A-Number (float), see function isnan
  NEG0 = -0.0
Negative 0.0 (float), see function isneg0
  PI2 = 6.28318530718
Two PI, PI * 2 aka Tau (float) # PYCHOK expected
  PI_2 = 1.57079632679
Half PI, PI / 2 (float)
  PI_4 = 0.785398163397
Quarter PI, PI / 4 (float)
  R_M = 6371008.77141
Mean, spherical earth radius (meter).
Function Details

clips (bstr, limit=50, white='')

 

Clip a string to the given length limit.

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

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).

isfinite (obj)

 

Check for Inf and NaN values.

Arguments:
  • obj - Value (scalar).
Returns:
False if obj is INF or NAN, True otherwise.
Raises:
  • TypeError - Non-scalar obj.

isint (obj, both=False)

 

Check for int type or an integer float value.

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

isneg0 (obj)

 

Check for NEG0, negative 0.0.

Arguments:
  • obj - Value (scalar).
Returns:
True if obj is NEG0 or -0.0, False otherwise.

isscalar (obj)

 

Check for scalar types.

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

issequence (obj, *excluded)

 

Check for sequence types.

Arguments:
  • obj - The object (any type).
  • excluded - Optional exclusions (type).
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, Super)

 

Check whether a class is a sub-class of a super class.

Arguments:
  • Sub - The sub-class (class).
  • Super - The super class (class).
Returns:
True if Sub is a sub-class of Super, False otherwise (bool).

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 (func, *xs)

 

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

Arguments:
  • func - 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 Python 2 behavior.

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

property_doc_ (doc)

 

Decorator for a property with documentation.

Arguments:
  • doc - The property documentation (str).

Example:

>>> @property_doc_("documentation text.")
>>> def name(self):
>>>     ...
>>>
>>> @name.setter
>>> def name(self, value):
>>>     ...