Python: TypeError: cannot concatenate ‘str’ and ‘int’ objects

I have this python program that adds strings to integers:

a = raw_input("Enter a: ")
b = raw_input("Enter b: ")
print "a + b as strings: " + a + b
a = int(a)
b = int(b)
c = a + b
str(c)
print "a + b as integers: " + c

I get this error:

Python: TypeError: cannot concatenate 'str' and 'int' objects

How can I add strings to integers?

Answers:

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Method 1

There are two ways to fix the problem which is caused by the last print statement.

You can assign the result of the str(c) call to c as correctly shown by @jamylak and then concatenate all of the strings, or you can replace the last print simply with this:

print "a + b as integers: ", c  # note the comma here

in which case

str(c)

isn’t necessary and can be deleted.

Output of sample run:

Enter a: 3
Enter b: 7
a + b as strings:  37
a + b as integers:  10

with:

a = raw_input("Enter a: ")
b = raw_input("Enter b: ")
print "a + b as strings: " + a + b  # + everywhere is ok since all are strings
a = int(a)
b = int(b)
c = a + b
print "a + b as integers: ", c

Method 2

str(c) returns a new string representation of c, and does not mutate c itself.

c = str(c)

is probably what you are looking for

Method 3

If you want to concatenate int or floats to a string you must use this:

i = 123
a = "foobar"
s = a + str(i)

Method 4

c = a + b 
str(c)

Actually, in this last line you are not changing the type of the variable c. If you do

c_str=str(c)
print "a + b as integers: " + c_str

it should work.

Method 5

Apart from other answers, one could also use format()

print("a + b as integers: {}".format(c))

For example –

hours = 13
minutes = 32
print("Time elapsed - {} hours and {} minutes".format(hours, minutes))

will result in output – Time elapsed - 13 hours and 32 minutes

Check out docs for more information.

Method 6

You can convert int into str using string function:

user = "mohan"

line = str(50)

print(user + "typed" + line + "lines")

Method 7

The easiest and least confusing solution:

a = raw_input("Enter a: ")
b = raw_input("Enter b: ")
print "a + b as strings: %s" % a  + b
a = int(a)
b = int(b)
c = a + b
print "a + b as integers: %d" % c

I found this on http://freecodeszone.blogspot.com/

Method 8

I also had the error message “TypeError: cannot concatenate ‘str’ and ‘int’ objects”. It turns out that I only just forgot to add str() around a variable when printing it. Here is my code:

def main():
    rolling = True; import random
    while rolling:
        roll = input("ENTER = roll; Q = quit ")
        if roll.lower() != 'q':
            num = (random.randint(1,6))
            print("----------------------"); print("you rolled " + str(num))
        else:
            rolling = False
main()

I know, it was a stupid mistake but for beginners who are very new to python such as myself, it happens.

Method 9

This is what i have done to get rid of this error separating variable with “,” helped me.

# Applying BODMAS 
arg3 = int((2 + 3) * 45 / - 2)
arg4 = "Value "
print arg4, "is", arg3

Here is the output

Value is -113

(program exited with code: 0)

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0