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Concatenation
 

As with integers and floats, strings in Python can be added, using a process called concatenation, which can be done on any two strings.
When concatenating strings, it doesn’t matter whether they’ve been created with single or double quotes. 

>> “Spam” + ‘eggs’
‘Spameggs’

>>> print(“First string” + “, “ + “second string”)
First string, second string 

 

NOTE!
You can’t concatenate strings with numbers (integers). Find out why in the next lesson.

Concatenation
 

Even if your strings contain numbers, they are still added as strings rather than integers. Adding a string to a number produces an error, as even though they might look similar, they are two different entities.

>> “2” + “2”
’22’
>>> 1 + ‘2’ + 3 + ‘4’
Traceback (most recent call last):
  File “<stdin>”, line 1, in <module>
TypeError: unsupported operand type(s) for +: ‘int’ and ‘str’ 

 

NOTE!
In future lessons, only the final line of error messages will be displayed, as it is the only one that gives details about the type of error that has occurred.

String Operations
 

Strings can also be multiplied by integers. This produces a repeated version of the original string. The order of the string and the integer doesn’t matter, but the string usually comes first.

Strings can’t be multiplied by other strings. Strings also can’t be multiplied by floats, even if the floats are whole numbers.

>> print(“spam” * 3)
spamspamspam

>>> 4 * ‘2’
‘2222’

>>> ’17’ * ’87’
TypeError: can‘t multiply sequence by non-int of type ‘str

>>> ‘pythonisfun‘ * 7.0
TypeError: can’t multiply sequence by nonint of type ‘float’ 

 

NOTE!
Try to multiply a string by 0 (zero) and see what happens.

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