Python正在打印每个字符？

Question

This is my code:

#Printing the original list (This was given)
a = ['spam','eggs',100,1234]
a[0:2] = [1,12]
print("This is the original list:", a)
#Prompting user to input data
b = input('Please add your first item to the list: ')
c = input('Please add your second item: ')
a[4:4] = b
a[5:5] = c
#Printing new list
print(a)

When I run it and add items to the list, it prints every character there, so hello becomes 'h','e','l','l','o' Even the numbers do this, could you help me fix this?

Answer 1

Because when you add strings to a list like that they become individual character inside the list:

In [5]: l = [1,2,3]

In [6]: s = "foo"

In [7]: l[1:1] = s

In [8]: l
Out[8]: [1, 'f', 'o', 'o', 2, 3]

If you want to add the strings to the end of the list use append :

In [9]: l = [1,2,3]

In [10]: s = "foo"

In [11]: l.append(s)

In [12]: l
Out[12]: [1, 2, 3, 'foo']

Or wrap the string in a list or use list.insert :

In [16]: l[1:1] = [s] # iterates over list not the string

In [17]: l
Out[17]: [1, 'foo', 2, 3, 'foo']
In [18]: l.insert(2,"foo")
In [18]: l
Out[19]: [1, 'foo', 'foo', 2, 3, 'foo']

Answer 2

note : tested only on python 2.7

the assignment operator expects an iterable in the right-hand side when you do

a[4:4] = b

so when you input a string, it treats it as an iterable and assigns each value of the iterable to the list. if you need to use the same code, use [string] for the input. else use list methods like append

Please add your first item to the list: ['srj']
Please add your second item: [2]
[1, 12, 100, 1234, 'srj', 2]