How do I swap 2 digits in an input given by the user?

Question

# Read an integer:
a = input()
#Now swap it...
a[0] = a[1]
a[1] = a[0]

As you can see I am trying to change the value and trying to swap it..

print(a)

...and then i print it out. But I am getting an error which is as follows:

Traceback (most recent call last):
  File "python", line 4, in <module>
TypeError: 'str' object does not support item assignment

For example, if my input is 79 I want the result to be 97. Can you tell me where my mistake is?

Strings are *immutable*, you cannot assign to characters by index. Search for your error message, there are lots of hits that will help you out. — jonrsharpe, Sep 08 '20 at 09:04
Do you expect the input to be two digits? If it can be more than two digits, which ones do you want to swap? — MisterMiyagi, Sep 08 '20 at 09:05
If the code worked it would still be broken: you're losing `a[0]`. — Andras Deak -- Слава Україні, Sep 08 '20 at 09:06
You need to introduce a new variable, to which you could assign something like: `s2 = str(int(s))[::-1]`. Casting to make sure that the input was an integer (although it does not ensure everything, e.g. that it has two digits only) — Maciek, Sep 08 '20 at 09:07

score 1 · Accepted Answer · answered Sep 08 '20 at 09:08

1

Try this:

a = input()
a = str(a)
result = int(a[-1: : -1])
print(result)

Output: ( a = 34 )

answered Sep 08 '20 at 09:08

Cosmos

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Note that there is no need to specify the starting index; ``[::-1]`` is sufficient. – MisterMiyagi Sep 08 '20 at 09:11

Avinash Dalvi · Answer 2 · 2020-09-08T09:20:30.013

0

Based on your question simple thing you can do. As above comment string is not iterable while you as input. You need to convert to list to access by index. For swap you need to use temporary variable, so i used temp as variable to swap.

a = list(input())
#Now swap it...

print(a)
temp = a[0]
a[0] = a[1]

a[1] = temp

print(a)
print("".join(a))

edited Sep 08 '20 at 09:20

answered Sep 08 '20 at 09:10

Avinash Dalvi

8,551
7
27
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I actually don't now what temp is....(I am just a beginner) – Cryptic Coder Sep 08 '20 at 09:13
For swap you need to use temporary variable, so i used temp as variable to swap. – Avinash Dalvi Sep 08 '20 at 09:15
1

Okay so,temp means temporary..... Thank you – Cryptic Coder Sep 08 '20 at 10:06

How do I swap 2 digits in an input given by the user?

2 Answers2