A set of 13 sensors transmit numerical data that is read every 5 minutes. To capture these values I used a dictionary of lists:
Sensors = {
'Sensor1':[10.52,12.45,15.70],
'Sensor5':[12.32,22.80,30.42],
'Sensor3':[4.7,3.4,2.1],
'Sensor8':[2.34,4.28,7.10],
'Sensor4':[10.64,14.76,4.25],
'Sensor2':[3.21,7.88,9.22],
'Sensor6':[4.11,9.32,2.70],
'Sensor9':[11.45,14.72,8.30],
'Sensor7':[6.10,3.98,10.66],
'Sensor10':[7.22,8.67,10.99],
'Sensor13':[1.19,4.65,0.87],
'Sensor12':[2.10,5.46,3.21],
'Sensor11':[5.80,8.22,14.39]
}
I need to sort this list so that the sensors that have had a positive increase appear at the top. To achieve this goal, I created another dictionary DeltaValues with the name of the sensor and the difference between the last and the first value captured:
DeltaValues={}
for x, y in Sensors.items():
if len(y) > 1:
DeltaValues[x] = format(y[-1] - y[0],'.2f')
else:
DeltaValues[x] = format(y[0],'.2f')
I used this syntax to sort:
sorted_d = {k: v for k, v in sorted(DeltaValues.items(), key=lambda x: x[1])}
But the result was not what I expected:
print(sorted_d)
{'Sensor13': '-0.32',
'Sensor6': '-1.41',
'Sensor3': '-2.60',
'Sensor9': '-3.15',
'Sensor4': '-6.39',
'Sensor12': '1.11',
'Sensor5': '18.10',
'Sensor10': '3.77',
'Sensor7': '4.56',
'Sensor8': '4.76',
'Sensor1': '5.18',
'Sensor2': '6.01',
'Sensor11': '8.59'}
Dicts do not guarantee to return the values in order in which they were put in.
Consider ordered dict. https://docs.python.org/3/library/collections.html#collections.OrderedDict
You could sort the (key, value)
pairs and leave them in a list:
>>> sorted(Sensors.items(), key= lambda sensor:sensor[1][-1] - sensor[1][0])
[('Sensor4', [10.64, 14.76, 4.25]), ('Sensor9', [11.45, 14.72, 8.3]), ('Sensor3', [4.7, 3.4, 2.1]), ('Sensor6', [4.11, 9.32, 2.7]), ('Sensor13', [1.19, 4.65, 0.87]), ('Sensor12', [2.1, 5.46, 3.21]), ('Sensor10', [7.22, 8.67, 10.99]), ('Sensor7', [6.1, 3.98, 10.66]), ('Sensor8', [2.34, 4.28, 7.1]), ('Sensor1', [10.52, 12.45, 15.7]), ('Sensor2', [3.21, 7.88, 9.22]), ('Sensor11', [5.8, 8.22, 14.39]), ('Sensor5', [12.32, 22.8, 30.42])]
Here is the solution
import operator
def getSortedSensorData():
sensors = {
'Sensor1':[10.52,12.45,15.70],
'Sensor5':[12.32,22.80,30.42],
'Sensor3':[4.7,3.4,2.1],
'Sensor8':[2.34,4.28,7.10],
'Sensor4':[10.64,14.76,4.25],
'Sensor2':[3.21,7.88,9.22],
'Sensor6':[4.11,9.32,2.70],
'Sensor9':[11.45,14.72,8.30],
'Sensor7':[6.10,3.98,10.66],
'Sensor10':[7.22,8.67,10.99],
'Sensor13':[1.19,4.65,0.87],
'Sensor12':[2.10,5.46,3.21],
'Sensor11':[5.80,8.22,14.39]
}
sensorData = {};
for sensor in sensors:
data = sensors[sensor]
data = sorted(data, reverse = True)
sensorData[sensor] = data[0];
sensorData = sorted( sensorData.items(), key=operator.itemgetter(1),reverse=True )
print( sensorData )
Output
[('Sensor5', 30.42), ('Sensor1', 15.7), ('Sensor4', 14.76), ('Sensor9', 14.72), ('Sensor11', 14.39), ('Sensor10', 10.99), ('Sensor7', 10.66), ('Sensor6', 9.32), ('Sensor2', 9.22), ('Sensor8', 7.1), ('Sensor12', 5.46), ('Sensor3', 4.7), ('Sensor13', 4.65)]
If you are on python 3.5+, use regular dict
as follows:
dict(sorted(Sensors.items(), key=lambda x: x[1][-1] - x[1][0], reverse=True))
Out[11]:
{'Sensor5': [12.32, 22.8, 30.42],
'Sensor11': [5.8, 8.22, 14.39],
'Sensor2': [3.21, 7.88, 9.22],
'Sensor1': [10.52, 12.45, 15.7],
'Sensor8': [2.34, 4.28, 7.1],
'Sensor7': [6.1, 3.98, 10.66],
'Sensor10': [7.22, 8.67, 10.99],
'Sensor12': [2.1, 5.46, 3.21],
'Sensor13': [1.19, 4.65, 0.87],
'Sensor6': [4.11, 9.32, 2.7],
'Sensor3': [4.7, 3.4, 2.1],
'Sensor9': [11.45, 14.72, 8.3],
'Sensor4': [10.64, 14.76, 4.25]}
If you are on python < 3.5+, use collecions.OrderedDict
as follows:
collections.OrderedDict(sorted(Sensors.items(), key=lambda x: x[1][-1] - x[1][0], reverse=True))
Out[2067]:
OrderedDict([('Sensor5', [12.32, 22.8, 30.42]),
('Sensor11', [5.8, 8.22, 14.39]),
('Sensor2', [3.21, 7.88, 9.22]),
('Sensor1', [10.52, 12.45, 15.7]),
('Sensor8', [2.34, 4.28, 7.1]),
('Sensor7', [6.1, 3.98, 10.66]),
('Sensor10', [7.22, 8.67, 10.99]),
('Sensor12', [2.1, 5.46, 3.21]),
('Sensor13', [1.19, 4.65, 0.87]),
('Sensor6', [4.11, 9.32, 2.7]),
('Sensor3', [4.7, 3.4, 2.1]),
('Sensor9', [11.45, 14.72, 8.3]),
('Sensor4', [10.64, 14.76, 4.25])])
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