Unable to understand this python code

python

Solution

Is it really necessary to use those brackets?

In Python 2.x, `print` is a statement, and the brackets are optional.

In Python 3.x, `print()` is a function, and the brackets are mandatory.

It is considered good practice to use brackets even in Python 2.x, to ease eventual transition to Python 3.x.

I am unable to understand these differences in the results. Could you shed some light on this?

Here is what happens when you print several comma-separated things in Python 2.x:

In [1]: print(1,2,3)
(1, 2, 3)

The above is interpreted as the `print` statement followed by a single argument, which is a tuple. The tuple is rendered with parentheses and commas.

In [2]: print 1,2,3
1 2 3

The above is interpreted as the `print` statement followed by three arguments. Each argument is printed out separately, with spaces between them.

Neither version is great as far as compatibility with Python 3 is concerned: the first version is rendered differently, and the second is simply not valid Python 3 code.

With this in mind, I recommend that you stick with:

print("Happy Birthday, dear " + person + ".")

This produces exactly the same results in both Python 2.x and Python 3.x.

Problem

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