Hi,
I've having trouble understanding the self concept as it applies to
variables. I think I understand how it affects methods.
I haven't been able to fully grasp the scope of class variables and
the effect of the "self" to the scope of the variable.
I (think) I understand that in the below case, the word self could be
replaced with "BME280" to explicitly call out a variable.
But even still I don't know how explicit call out effects the scope of
a variable.
The below pseudo code is distilled from my 1st attempt at a functional
Python program on the RasPi.
My questions are:
What is the scope of class variables?
does the self. prefix modify this scope?
Thanks
Regards
JonRob
#!/usr/bin/python
# -- developed using Python 2.7.3
class BME280:
# all the below are class variables
# those preceded by an underscore are predefined to some constant
# those without the underscore are to be "working" variables.
_regT1 = 0x88
_regH6 = 0xE7
_coeff_P2 = 0x82
_coeff_P6 = 0x32
filter = 0 #should these be "self"?
t_fine = 0
def __init__(self, address=0x76, debug=True):
self.i2c = Adafruit_I2C(address)
self.address = address
self.debug = debug
def pressure_calc(self):
var1 = self.i2c.readU16(self._regT1,False)
p = (1048576.0 - var1) * _coeff_P2
return p
def read_pressure(self): #called by main application
pressure_hPa = pressure_calc(self) /10
# apply compensation
return pressure_hPa
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