创建元组列表，将元组元素用作输入

Question

I wish to create a list whose members are tuples, taken from console input. I've seen other questions which describe about tuples and lists. But how to create tuples from input and append them to list till the choice to take tuple elements is no, 'n'? I tried the following code.

"""
Create the tuples into a list.
"""

def createTupledList() :
    l=[]
    print("Add an element for the tuple ? y/n : ")
    ch=str(input())
    while(ch=='y') :
        print("Enter the tuple element : ")
        i=input()
        l=l.append(tuple(i))
        print("Add an element for the tuple ? y/n : ")
        ch=str(input())
    return l



l2=createTupledList()
print(l2)

Please help.

My inputs and error output :

C:\Users\vikranth\myproject\Python\Lists\Day 0>py tuplesortlist.py
Add an element for the tuple ? y/n :
y
Enter the tuple element :
1
Add an element for the tuple ? y/n :
y
Enter the tuple element :
2
Traceback (most recent call last):
  File "tuplesortlist.py", line 19, in <module>
    l2=createTupledList()
  File "tuplesortlist.py", line 12, in createTupledList
    l=l.append(tuple(i))
AttributeError: 'NoneType' object has no attribute 'append'

Answer 1

The append() function does not return an appended list, it returns a NoneType because it performs the append in place , so you can simply change the line:

l=l.append(tuple(i))

to:

l.append(tuple(i))

and this should work.

Answer 2

Code to add multiple elements into a tuple and to add multiple tuples to a list.

"""
Create the tuples into a list.
"""

def createTupledList() :
    l=[]
    while True:
      t=tuple()
      print("Add an element for the tuple ? y/n : ")
      if input()!='y':
        break
      else:
        print("Keep adding the tuple elements : (x to break)")
        while True:
          i=input()
          if i=='x':
            break
          else:
            t+=(i,)
          print(t)
        l.append(t)
    return l

l2=createTupledList()
print(l2)