如何从字典中的键获取值

Question

I have some code for car registration for parking. I have created a dictionary with car registration number as keys and rest information as values. I am trying to get details (values) of each registration by entering the registration number. Even if the id is in the dictionary it's showing message not found in the dictionary.

global variable
data_dict = {}
def createNameDict(filename):
  path = "C:\Users\user\Desktop"
  basename = "ParkingData_Part2.txt"
  filename = path + "\\" + basename
  file = open(filename)
  contents = file.read()
  print contents,"\n"


  data_list = [lines.split(",",1) for lines in contents.split("\n")]
  #data_list.sort()
  #print data_list 
  #dict_list = []

  for line in data_list:
    keys = line[0]
    values = line[1]

    data_dict[keys] = values
  print data_dict,"\n"
  print data_dict.keys(),"\n"
  print data_dict.values(),"\n"
  print data_list  
def detailForRegistrationNumber(regNumber):
  regNumber == "keys"
  if regNumber in data_dict:
    print data_dict[regNumber]
  else:
    print regNumber, "Not in dictionary" 

The error message I am getting is:

======= Loading Progam =======
>>> detailForRegistrationNumber('EDF768')
EDF768 Not in dictionary

But the dictionary has the above registration number:

{'HUY768': ' Wilbur Matty, 8912, Creche_Parking', 'GH7682': ' Clara Hill, 7689, AgHort_Parking', 'GEF123': ' Jill Black, 3456, Creche_Parking', 'WER546': ' Olga Grey, 9898, Creche_Parking', 'TY5678': ' Jane Miller, 8987, AgHort_Parking', 'ABC234': ' Fred Greenside, 2345, AgHort_Parking', 'KLOI98': ' Martha Miller, 4563, Vet_Parking', **'EDF768'**: ' Bill Meyer, 2456, Vet_Parking', 'JU9807': ' Jacky Blair, 7867, Vet_Parking', 'DF7800': ' Jacko Frizzle, 4532, Creche_Parking', 'ADF645': ' Cloe Freckle, 6789, Vet_Parking'}

Answer 1

I think your problem is that your function def createNameDict(filename): doesn't return anything, so the data_dict inside it is just a local variable!

Make the last line of the function return data_dict and then use it like data_dict = createNameDict(filename) . There is no need for the global variable part, so just remove that.