Python Programming

The + operator concatenates (joins) two strings together.

Python returns a TypeError: can only concatenate str (not "int") to str. You cannot add an int to a str in Python. You can only concatenate two str instances.

Python returns a TypeError: unsupported operand type(s) for -: 'str' and 'str'. Python is basically saying: you cannot use the "minus" operator with str operands.

The multiplication operator actually works for strings. It will replicate the string $N$ times.

The multiplication operator also works with an integer as the first operand and a string as the second. Like the previous question, it will replicate the string $N$ times.

Alas, this does not work! What is the error returned by Python? (Try this in an interactive prompt!). In summary, you can only multiply a str by an int. You cannot multiply two str (what are you expecting to happen anyway?)

Again, "3" is a str. You cannot multiply two strings.

According to operator precedence, Python will first execute the multiplication operation "happy" * 3 resulting in "happyhappyhappy". It will then concatenate the three strings: "i am", " " (space), "happyhappyhappy", resulting in "i am happyhappyhappy".

According to operator precedence, Python will first execute the multiplication operation "i am" * 3 resulting in "i ami ami am" (note the lack of space). It will then concatenate the two strings resulting in "i ami ami amhappy".

According to operator precedence, Python will first execute the expression inside the parenthesis, and so will concatenate the three strings resulting in "i am happy". It will then perform the multiplication and so will replicate the string, resulting in "i am happyi am happyi am happy".