from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from __future__ import unicode_literals
import decimal
import math
import re
import six
[docs]def to_int(input_, default=0, exception=(ValueError, TypeError), regexp=None):
r'''
Convert the given input to an integer or return default
When trying to convert the exceptions given in the exception parameter
are automatically catched and the default will be returned.
The regexp parameter allows for a regular expression to find the digits
in a string.
When True it will automatically match any digit in the string.
When a (regexp) object (has a search method) is given, that will be used.
WHen a string is given, re.compile will be run over it first
The last group of the regexp will be used as value
>>> to_int('abc')
0
>>> to_int('1')
1
>>> to_int('abc123')
0
>>> to_int('123abc')
0
>>> to_int('abc123', regexp=True)
123
>>> to_int('123abc', regexp=True)
123
>>> to_int('abc123abc', regexp=True)
123
>>> to_int('abc123abc456', regexp=True)
123
>>> to_int('abc123', regexp=re.compile(r'(\d+)'))
123
>>> to_int('123abc', regexp=re.compile(r'(\d+)'))
123
>>> to_int('abc123abc', regexp=re.compile(r'(\d+)'))
123
>>> to_int('abc123abc456', regexp=re.compile(r'(\d+)'))
123
>>> to_int('abc123', regexp=r'(\d+)')
123
>>> to_int('123abc', regexp=r'(\d+)')
123
>>> to_int('abc', regexp=r'(\d+)')
0
>>> to_int('abc123abc', regexp=r'(\d+)')
123
>>> to_int('abc123abc456', regexp=r'(\d+)')
123
>>> to_int('1234', default=1)
1234
>>> to_int('abc', default=1)
1
>>> to_int('abc', regexp=123)
Traceback (most recent call last):
...
TypeError: unknown argument for regexp parameter: 123
'''
if regexp is True:
regexp = re.compile(r'(\d+)')
elif isinstance(regexp, six.string_types):
regexp = re.compile(regexp)
elif hasattr(regexp, 'search'):
pass
elif regexp is not None:
raise TypeError('unknown argument for regexp parameter: %r' % regexp)
try:
if regexp:
match = regexp.search(input_)
if match:
input_ = match.groups()[-1]
return int(input_)
except exception:
return default
[docs]def to_float(input_, default=0, exception=(ValueError, TypeError),
regexp=None):
r'''
Convert the given `input_` to an integer or return default
When trying to convert the exceptions given in the exception parameter
are automatically catched and the default will be returned.
The regexp parameter allows for a regular expression to find the digits
in a string.
When True it will automatically match any digit in the string.
When a (regexp) object (has a search method) is given, that will be used.
WHen a string is given, re.compile will be run over it first
The last group of the regexp will be used as value
>>> '%.2f' % to_float('abc')
'0.00'
>>> '%.2f' % to_float('1')
'1.00'
>>> '%.2f' % to_float('abc123.456', regexp=True)
'123.46'
>>> '%.2f' % to_float('abc123', regexp=True)
'123.00'
>>> '%.2f' % to_float('abc0.456', regexp=True)
'0.46'
>>> '%.2f' % to_float('abc123.456', regexp=re.compile(r'(\d+\.\d+)'))
'123.46'
>>> '%.2f' % to_float('123.456abc', regexp=re.compile(r'(\d+\.\d+)'))
'123.46'
>>> '%.2f' % to_float('abc123.46abc', regexp=re.compile(r'(\d+\.\d+)'))
'123.46'
>>> '%.2f' % to_float('abc123abc456', regexp=re.compile(r'(\d+(\.\d+|))'))
'123.00'
>>> '%.2f' % to_float('abc', regexp=r'(\d+)')
'0.00'
>>> '%.2f' % to_float('abc123', regexp=r'(\d+)')
'123.00'
>>> '%.2f' % to_float('123abc', regexp=r'(\d+)')
'123.00'
>>> '%.2f' % to_float('abc123abc', regexp=r'(\d+)')
'123.00'
>>> '%.2f' % to_float('abc123abc456', regexp=r'(\d+)')
'123.00'
>>> '%.2f' % to_float('1234', default=1)
'1234.00'
>>> '%.2f' % to_float('abc', default=1)
'1.00'
>>> '%.2f' % to_float('abc', regexp=123)
Traceback (most recent call last):
...
TypeError: unknown argument for regexp parameter
'''
if regexp is True:
regexp = re.compile(r'(\d+(\.\d+|))')
elif isinstance(regexp, six.string_types):
regexp = re.compile(regexp)
elif hasattr(regexp, 'search'):
pass
elif regexp is not None:
raise TypeError('unknown argument for regexp parameter')
try:
if regexp:
match = regexp.search(input_)
if match:
input_ = match.group(1)
return float(input_)
except exception:
return default
[docs]def to_unicode(input_, encoding='utf-8', errors='replace'):
'''Convert objects to unicode, if needed decodes string with the given
encoding and errors settings.
:rtype: unicode
>>> to_unicode(b'a')
'a'
>>> to_unicode('a')
'a'
>>> to_unicode(u'a')
'a'
>>> class Foo(object): __str__ = lambda s: u'a'
>>> to_unicode(Foo())
'a'
>>> to_unicode(Foo)
"<class 'python_utils.converters.Foo'>"
'''
if isinstance(input_, six.binary_type):
input_ = input_.decode(encoding, errors)
else:
input_ = six.text_type(input_)
return input_
[docs]def to_str(input_, encoding='utf-8', errors='replace'):
'''Convert objects to string, encodes to the given encoding
:rtype: str
>>> to_str('a')
b'a'
>>> to_str(u'a')
b'a'
>>> to_str(b'a')
b'a'
>>> class Foo(object): __str__ = lambda s: u'a'
>>> to_str(Foo())
'a'
>>> to_str(Foo)
"<class 'python_utils.converters.Foo'>"
'''
if isinstance(input_, six.binary_type):
pass
else:
if not hasattr(input_, 'encode'):
input_ = six.text_type(input_)
input_ = input_.encode(encoding, errors)
return input_
[docs]def scale_1024(x, n_prefixes):
'''Scale a number down to a suitable size, based on powers of 1024.
Returns the scaled number and the power of 1024 used.
Use to format numbers of bytes to KiB, MiB, etc.
>>> scale_1024(310, 3)
(310.0, 0)
>>> scale_1024(2048, 3)
(2.0, 1)
>>> scale_1024(0, 2)
(0.0, 0)
>>> scale_1024(0.5, 2)
(0.5, 0)
>>> scale_1024(1, 2)
(1.0, 0)
'''
if x <= 0:
power = 0
else:
power = min(int(math.log(x, 2) / 10), n_prefixes - 1)
scaled = float(x) / (2 ** (10 * power))
return scaled, power
[docs]def remap(value, old_min, old_max, new_min, new_max):
'''
remap a value from one range into another.
>>> remap(500, 0, 1000, 0, 100)
50
>>> remap(250.0, 0.0, 1000.0, 0.0, 100.0)
25.0
>>> remap(-75, -100, 0, -1000, 0)
-750
>>> remap(33, 0, 100, -500, 500)
-170
>>> remap(decimal.Decimal('250.0'), 0.0, 1000.0, 0.0, 100.0)
Decimal('25.0')
This is a great use case example. Take an AVR that has dB values the
minimum being -80dB and the maximum being 10dB and you want to convert
volume percent to the equilivint in that dB range
>>> remap(46.0, 0.0, 100.0, -80.0, 10.0)
-38.6
I added using decimal.Decimal so floating point math errors can be avoided.
Here is an example of a floating point math error
>>> 0.1 + 0.1 + 0.1
0.30000000000000004
If floating point remaps need to be done my suggstion is to pass at least
one parameter as a `decimal.Decimal`. This will ensure that the output
from this function is accurate. I left passing `floats` for backwards
compatability and there is no conversion done from float to
`decimal.Decimal` unless one of the passed parameters has a type of
`decimal.Decimal`. This will ensure that any existing code that uses this
funtion will work exactly how it has in the past.
Some edge cases to test
>>> remap(1, 0, 0, 1, 2)
Traceback (most recent call last):
...
ValueError: Input range (0-0) is empty
>>> remap(1, 1, 2, 0, 0)
Traceback (most recent call last):
...
ValueError: Output range (0-0) is empty
:param value: value to be converted
:type value: int, float, decimal.Decimal
:param old_min: minimum of the range for the value that has been passed
:type old_min: int, float, decimal.Decimal
:param old_max: maximum of the range for the value that has been passed
:type old_max: int, float, decimal.Decimal
:param new_min: the minimum of the new range
:type new_min: int, float, decimal.Decimal
:param new_max: the maximum of the new range
:type new_max: int, float, decimal.Decimal
:return: value that has been re ranged. if any of the parameters passed is
a `decimal.Decimal` all of the parameters will be converted to
`decimal.Decimal`. The same thing also happens if one of the
parameters is a `float`. otherwise all parameters will get converted
into an `int`. technically you can pass a `str` of an integer and it
will get converted. The returned value type will be `decimal.Decimal`
of any of the passed parameters ar `decimal.Decimal`, the return type
will be `float` if any of the passed parameters are a `float` otherwise
the returned type will be `int`.
:rtype: int, float, decimal.Decimal
'''
if (
isinstance(value, decimal.Decimal) or
isinstance(old_min, decimal.Decimal) or
isinstance(old_max, decimal.Decimal) or
isinstance(new_min, decimal.Decimal) or
isinstance(new_max, decimal.Decimal)
):
type_ = decimal.Decimal
elif (
isinstance(value, float) or
isinstance(old_min, float) or
isinstance(old_max, float) or
isinstance(new_min, float) or
isinstance(new_max, float)
):
type_ = float
else:
type_ = int
value = type_(value)
old_min = type_(old_min)
old_max = type_(old_max)
new_max = type_(new_max)
new_min = type_(new_min)
old_range = old_max - old_min
new_range = new_max - new_min
if old_range == 0:
raise ValueError('Input range ({}-{}) is empty'.format(
old_min, old_max))
if new_range == 0:
raise ValueError('Output range ({}-{}) is empty'.format(
new_min, new_max))
new_value = (value - old_min) * new_range
if type_ == int:
new_value //= old_range
else:
new_value /= old_range
new_value += new_min
return new_value