can only concatenate str (not 'int') to str

Question

I want to make a simple addition program but get stuck at an error stating the following: TypeError: can only concatenate str (not 'int') to str.

I have no idea what to do, I am pretty new to Python coding.

def addition():
    x = int(input("Please enter the first number:"))
    y = int(input("Please enter the second number:"))
    z = x+y
    print("The sum of " +x+ " and " +y+ " gives " +z )

I expect the code to return the value of the sum of the two entered values.

I suggest you read the [official Python tutorial](https://docs.python.org/3/tutorial/), it's quite good. — mkrieger1, Dec 26 '18 at 16:29
Thanks a lot, to everybody that helped, I know it was a silly question, but still I am quite new in Python coding. Thanks a lot again... — Sumedh, Dec 26 '18 at 17:06

Pedro Martins de Souza · Accepted Answer · 2018-12-26T16:49:57.370

2

The + operator can work in multiple contexts. In this case, the relevant use cases are:

When concatenating stuff (strings, for example);
When you want to add numbers (int, float and so on).

So when you use the + in a concept that uses both strings and int variables (x, y and z), Python won't handle your intention correctly. In your case, in which you want to concatenate numbers in the sentence as if they were words, you'd have to convert your numbers from int format to string format. Here, see below:

def addition():
    x = int(input("Please enter the first number:"))
    y = int(input("Please enter the second number:"))
    z = x+y
    print("The sum of " + str(x) + " and " + str(y) + " gives " + str(z))

edited Dec 26 '18 at 16:49

answered Dec 26 '18 at 16:29

Pedro Martins de Souza

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"It can only handle strings". Really? What about lists,? – roganjosh Dec 26 '18 at 16:42
1

Oops, my mistake! Improved it, thanks for the warning! – Pedro Martins de Souza Dec 26 '18 at 16:44
Appreciate the edit but I think you've been too hasty :) now you're saying that `+` will not work with numbers. The fact is that the symbol will be interpreted differently based on types. – roganjosh Dec 26 '18 at 16:45
1

In a context in which you use strings, the `+` will work as a concatenate operator. But I see your point. Just give me a second to better put why Python will be in conflict. – Pedro Martins de Souza Dec 26 '18 at 16:46
1

Okay, fixed. Thanks very much for the advices and the patience :) – Pedro Martins de Souza Dec 26 '18 at 16:53

score 1 · Answer 2 · answered Dec 26 '18 at 16:29

1

The problem is when you print the output (print("The sum of " +x+ " and " +y+ " gives " +z )), you are adding strings to integers (x, y, and z).

Try replace it with

print("The sum of {0} and {1} gives {2}".format(x, y, z))

answered Dec 26 '18 at 16:29

Xiaoyu Lu

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can only concatenate str (not 'int') to str

2 Answers2