python - 将字典值转换为整数

Question

我在将一些数字从字符串转换为整数时遇到问题。这是有问题的功能:

def read_discounts():
  myFile = open('discount.txt', 'r')
  discountValues = {}

  #read and split first line
  firstLine = myFile.readline()
  firstLine = re.sub(r'\$','',firstLine)
  firstLine = re.sub(r'\%','',firstLine)
  firstLine = firstLine.split()

  #add values to dictionary
  discountValues['UpperLimit1'] = {firstLine[2]}
  int(discountValues['UpperLimit1'])
  discountValues['PercentDiscount1'] = {firstLine[4]}

和回溯:

Traceback (most recent call last):
File "C:\Users\Sam\Desktop\test.py", line 94, in <module>
main()
File "C:\Users\Sam\Desktop\test.py", line 6, in main
discounts = read_discounts()
File "C:\Users\Sam\Desktop\test.py", line 33, in read_discounts
int(discountValues['UpperLimit1'])
TypeError: int() argument must be a string or a number, not 'set'

我有点不知所云，但我知道 discountValues['UpperLimit'] 是一个应该能够转换为整数的值(100)

我尝试过的: 我尝试在将字符串列表中的值添加到字典之前对其进行转换，但我得到了相同的结果。我也尝试过使用字典理解，但是当我稍后使用该值时，这似乎会导致问题。

如有任何建议，我们将不胜感激，谢谢。

Answer 1

您以错误的方式分配字典值。应该是

discountValues['UpperLimit1'] = firstLine[2] # Droped the { and } from assignment
int(discountValues['UpperLimit1'])
discountValues['PercentDiscount1'] = firstLine[4]

在 {} 中结束内容将创建 sets in python3

测试

>>> a_dict = {}
>>> a_dict["set"] = {"1"} # creates a set and assign it to a_dict["set"]
>>> type(a_dict["set"])
<class 'set'>
>>> a_dict["string"] = "1" # Here a string value is assigned to a_dict["string"]

>>> type(a_dict["string"])
<class 'str'>

>>> int(a_dict["string"])
1
>>> int(a_dict["set"])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: int() argument must be a string, a bytes-like object or a number, not 'set'

---

编辑

如果您尝试将整数值分配给字典键，则必须在分配时完成，例如

discountValues['UpperLimit1'] = int(firstLine[2]) # int() converts string to int
discountValues['PercentDiscount1'] = int(firstLine[4])