why is this variable not printing out properly?

[dursland]

Using python3 and am new - learning via introtopython.org and I'm having a problem.

var1 = (2+2)

print('The result of all calculations is ' + var1 + ' and we are done.')

Which returns the error of

Traceback (most recent call last):
  File "test.py", line 3, in <module>
    print('The result of all calculations is ' + var1 + ' and we are done.')
TypeError: Can't convert 'int' object to str implicitly

What am I doing wrong? When I change the variable to a string the line executes properly.

[Mekire]

When I change the variable to a string the line executes properly.

That is exactly it.  You can't concatenate a string and int.

The recommended way would be to use format.  String concatenation in general is not a great technique (though often the first thing taught >.>)

var1 = 2 + 2
 
print('The result of all calculations is {} and we are done.'.format(var1))

[wavic]

Hello!
Using '+' for a string concatenation works but for strings. You are trying to concatenate a string with an integer without to convert the number into string - str(num).

@Mekire has showed you the proper way

[dursland]

Thanks. Good to know, I'm following the lessons in order on introtopython.

[snippsat]

Now that 3.6 is out,also f-string.

>>> var1 = 2 + 2
>>> print(f'The result of all calculations is {var1} and we are done.')
The result of all calculations is 4 and we are done.

[Mekire]

Now that 3.6 is out,also f-string.

Wow. That is a pretty neat addition.

[sixteenornumber]

here is one more method.

>>> var1 = 2 + 2
>>> print "the result of all calculations is %s and we are done." % var1
the result of all calculations is 4 and we are done.

you can also print floats to a specific decimal place. 

>>> PI = 3.14159265389793
>>> print "Pi to the 2nd decimal place is %.02f" %PI
Pi to the 2nd decimal place is 3.14
>>> print "Pi to the 3rd decimal place is \"%.03f\" and pi to the 4th decimal place is \"%.04f\"." %(PI, PI)
Pi to the 3rd decimal place is "3.141" and pi to the 4th decimal place is "3.1415".

[Mekire]

The % method of string formatting should really be considered deprecated (despite Zed's irrelevant opinion).
Everything that can be done with it can be done much more cleanly with format.

[samRddhi]

Use

print('The result of all calculations is ' + str(var1) + ' and we are done.')

[IAMK]

The recommended way would be to use format.  String concatenation in general is not a great technique (though often the first thing taught >.>)

var1 = 2 + 2
 
print('The result of all calculations is {} and we are done.'.format(var1))

Could you please explain why that is?
To me, a simple typecast to string seems cleaner.