9.2. Operations on Strings¶

In general, you cannot perform mathematical operations on strings, even if the strings look like numbers. The following are illegal (assuming that message has type str):

message - 1
"Hello" / 123
"15" + 2

Interestingly, the + operator does work with strings, but for strings, the + operator represents concatenation, not addition. Concatenation means joining the two operands by linking them end-to-end. For example:

fruit: str

baked_good: str

fruit = "banana"

baked_good = " nut bread"

print(fruit + baked_good)

​

The output of this program is banana nut bread. The space before the word nut is part of the string and is necessary to produce the space between the concatenated strings. Take out the space and run it again.

Check your understanding

s: str
t: str
s = "python"
t = "rocks"
print(s + t)