Python : How to properly implement a raise an exception in a function-CodePudding

I am trying to make a function that receives a list/array and returns the index of the maximum value in that sequence. The function should raise an exception if non-numerical values are present in the list.

def maxvalue(values):
    """
    Function that receives a list/array and returns the index of the maximum
    value in that sequence

    """    
    indices = []
    max_value = max(values)
    for i in range(len(values)):
        if type(i) not in (float, int): # raise an exception if the value is not float or integer
            raise TypeError("Only numberical values are allowed")
        if values[i] == max_value:
            indices.append(i)
    return indices

maxvalue([1, 1, 1.5, "e", 235.8, 9, 220, 220])

The function works when it receives a list containing floats and integers and doesn't work if there is a string in it.

How do I get the function to produce "TypeError("Only numberical values are allowed")" error quote when there is a str present in the list?

Currently, it produces "TypeError: '>' not supported between instances of 'str' and 'float'"

CodePudding user response：

The 'Comparison' happens in max function which raises an exception.

You should do all checks, before your logic.

def maxvalue(values):
    """
    Function that receives a list/array and returns the index of the maximum
    value in that sequence

    """

    try:
        max_value = max(values)
    except TypeError:
        raise TypeError("Only numberical values are allowed")

    indices = []
    for idx, val in enumerate(values):
        if val == max_value:
            indices.append(idx)

    return indices

As you can see i am catching TypeError and re-raise it with different message. Also use enumerate in for loops.

CodePudding user response：

def maxvalue(values):
  indices = []
  print(values)
  int_values = []
  """the max function cannot fetch a max value with a string as part of the list so you can filter the list to get only integer values before you get max value"""
  for x in values: 
      if type(x)==int:
          int_values.append(x)

  max_value = max(int_values)

  for i in range(len(int_values)):
      if int_values[i] == max_value:
              indices.append(i)
  return indices

print(maxvalue([1, 1, 1.5, "e", 235.8, 9, 220, 220]))