import numpy as np
value_int8 = np.int8(127)
value_uint8 = np.uint8(255)
Or you make your own type in Python:
class Int8(int):
def __init__(self, value):
if not -128 <= value <= 127:
raise ValueError('-128 <= int8 <= 127')But this still allows to get bigger or smaller values than allowed, after a calculation.
If there is a limit, just use if-statements to check if the value is in range.
If you need to be flexible with size, you can make a validator closure (function in a function).
def in_range(min_val, max_val):
"""
Closure to create a new function to check
if the given value is in range.
"""
def check(value):
# min_val and max_val is from the first call
return min_val <= value <= max_val # <- this is the second call
return check # <- returns the inner function, without calling it
def in_range_exc(min_val, max_val):
"""
Closure to create a new function to check
if the given value is in range. If not,
a ValueError is raised.
"""
def check(value):
if not min_val <= value <= max_val:
raise ValueError(f'{min_val} <= {value} <= {max_val}')
return check
voltage_ok = in_range(-10, +10)
current_ok = in_range(-0.02, +0.02)
power_ok = in_range(10, 11)
print(voltage_ok(0))
print(voltage_ok(1))
print(voltage_ok(10))
print(voltage_ok(-10))
print(voltage_ok(-10.00000000000000000000000001)) # < this is True, try to find out why
print(voltage_ok(-10.001))
voltage_ok_exc = in_range_exc(5, 5.1)
current_voltage = 5.10001
try:
voltage_ok_exc(current_voltage)
except ValueError:
print(f'The voltage {current_voltage}V is not in range')Usually you need this data types (int8, int16 ...) if you want to interact with C.
In this case
ctypes is the right module for it.
If you want to handle data over network/serial or in general binary data, you sould look for the
struct and
binascii module.
