Exercise $1\mathrm{.}1.$ It is a good idea to read this book in front of a computer so you can try out the

examples as you go$.$

Whenever you are experimenting with a new feature, you should try to make mistakes. For example,

in the $$Hello$,$ world!$$ program, what happens if you leave out one of the quotation marks? What if

you leave out both? What if you spell print wrong?

This kind of experiment helps you remember what you read; it also helps when you are programming,

because you get to know what the error messages mean. It is better to make mistakes now and on

purpose than later and accidentally.

$1.$ In a print statement, what happens if you leave out one of the parentheses, or both?

$2.$ If you are trying to print a string, what happens if you leave out one of the quotation marks,

or both?

$3.$ You can use a minus sign to make a negative number like $-2.$ What happens if you put a plus

sign before a number? What about $2++2?$

ChatGPT

These are great questions for exploring and understanding the basics of Python syntax and behavior. Let's address each one:

Leaving out parentheses in a print statement:

If you leave out one of the parentheses in a print statement, Python will throw a syntax error because it expects a closing parenthesis to match every opening parenthesis.

If you leave out both parentheses, Python will throw an error as well. In Python $3,$ print is a function, so it requires parentheses to work correctly.

Leaving out quotation marks when printing a string:

If you leave out one of the quotation marks, Python will not recognize the end of the string and will continue to read the next lines of code as part of the string until it encounters another quotation mark or throws a syntax error.

If you leave out both quotation marks, Python will interpret the text as a variable or keyword. If the text does not match any known variable or keyword, it will result in a name error.

Using a plus sign before a number:

Putting a plus sign before a number does not change its value. For example, $+3$ is still $3.$ The plus sign is generally redundant in this context.

For the expression $2++2,$ Python interprets the extra $+$ as a unary plus operator, which does not change the sign of the following number. This expression is equivalent to $2+2,$ so it will output $4.$

These experiments are a good way to get familiar with how Python's syntax and error handling work. It's important to read and understand error messages

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