Home/ Questions/Resolved the problem of the valueerror: max() arg is an empty sequence
Next
Answered
Lachlan Gagnon
  • 7
Asked: 2022-05-18T16:00:44+00:00 In:

Resolved the problem of the valueerror: max() arg is an empty sequence

  • 7

. Advertisement .

..3..

. Advertisement .

..4..

I have the following python code, but I do not know how to find the correct result. Why has this problem occurred, and how can it be solved?
Here is the code that I am running:

import wx
 import myLoopGUI
 import commands
 
 class MyLoopFrame(myLoopGUI.MyFrame1):
  def __init__(self, parent):
  myLoopGUI.MyFrame1.__init__(self, parent)
 
  def clkAddData(self,parent):
  if len(self.txtAddData.Value) != 0:
  try:
  myname = str(self.txtAddData.Value)
  self.listMyData.Append(str(myname))
  except:
  wx.MessageBox("This has to be a name!") 
  else:
  wx.MessageBox("This can't be empty")
 
 
 
 
  def clkFindMost(self, parent):
  self.listMyData = []
  unique_names = set(self.listMyData)
  frequencies = {}
  for name in unique_names:
  if frequencies.get[name]:
  frequencies[name] += 1
  else:
  frequencies[name] = 0
 
  v = list(frequencies.values())
  k = list(frequencies.keys())
  self.txtResults.Value = k.index(max(v))
 
 
  def clkFindLeast(self, parent):
  unique_names = set(self.listMyData)
  frequencies = {}
  for name in unique_names:
  if frequencies.get(name):
  frequencies[name] += 1
  else:
  frequencies[name] = 0
 
  v = list(frequencies.values())
  k = list(frequencies.keys())
  self.txtResults.Value = k.index(min(v))
 
 myApp = wx.App(False)
 myFrame = MyLoopFrame(None)
 myFrame.Show()
 myApp.MainLoop()

And this is the error text I receive:

ValueError: max() arg is an empty sequence

valueerror
Share

2 Answers

  1. Best Answer
    Expert

    The cause: Because in clkFindMost, you always set self.listMyData to an empty list. As both unique_names and frequencies are empty iterables after that, your code will always result in this error.
    In addition, you can’t use [] with dict.get because it’s a method, not a list/dictionary:

    Solution:

    To fix “valueerror: max() arg is an empty sequence”, you can follow my methods:

    Run the right code using () instead of []

    if frequencies.get(name):

    It returns an error, when an empty iterable is supplied to max() and min(). Before running max() on v, you can check its length.

    >>> lst = []
>>> max(lst)

Traceback (most recent call last):
File "<pyshell#2>", line 1, in <module>
max(lst)
ValueError: max() arg is an empty sequence
>>> if lst:
mx = max(lst)
else:
#Handle this here

    If it is being used with an iterator, you’ll need to consume it first before executing max() on it, while the iterator’s boolean value is always True, so we can’t use if instantly. Do like the following:

    >>> it = iter([])
>>> bool(it)
True
>>> lst = list(it)
>>> if lst:
mx = max(lst)
else:
#Handle this here

     

    • 0

  2. If the sequence is empty, pass a default value that can be returned to max by passing: 

    max(v, default=0)
    • 24

Leave an answer

You must login to add an answer.

Need An Account,