Python Essentials 1: Module 2

right

Use this snippet of code: print(2 ** 2 ** 3) The two possible results are: 2 ** 2 → 4; 4 ** 3 → 64 2 ** 3 → 8; 2 ** 8 → 256 Run the code. What do you see? The result clearly shows that the exponentiation operator uses rig_______________-sided binding.

Import

Fortunately, due to the fact that Python is case-sensitive, you can modify any of these words by changing the case of any letter, thus creating a new word, which is not reserved anymore. For example - you can't name your variable like this: import You mustn't have a variable named in such a way - it is prohibited. But you can do this instead: _____mport

describe unambiguous

Good, responsible developers descr_____________ each important piece of code, e.g., explaining the role of the variables; although it must be stated that the best way of commenting variables is to name them in an unambi_____________ manner.

upper lower digits character letter different reserved

If you want to give a name to a variable, you must follow some strict rules: the name of the variable must be composed of up___________-case or lo____________-case letters, dig_______________, and the character _ (underscore) the name of the variable must begin with a let____________; the underscore character is a letter; upper- and lower-case letters are treated as diffe____________ (a little differently than in the real world - Alice and ALICE are the same first names, but in Python they are two different variable names, and consequently, two different variables); the name of the variable must not be any of Python's reser________________ words (the keywords - we'll explain more about this soon).

miles_to_kilometers = miles * 1.61 kilometers_to_miles = kilometers / 1.61 7.38 miles is 11.88 kilometers 12.25 kilometers is 7.61 miles

Miles and kilometers are units of length or distance. Bearing in mind that 1 mile is equal to approximately 1.61 kilometers, complete the program in the editor so that it converts: miles to kilometers; kilometers to miles. kilometers = 12.25 miles = 7.38 miles_to_kilometers = kilometers_to_miles = print(miles, "miles is", round(miles_to_kilometers, 2), "kilometers") print (kilometers, "kilometers is", round (kilometers_to_miles, 2), "miles")

ordinary function parentheses

Note: to distinguish ordi__________________ words from funct__________________ names, place a pair of empty paren__________________after their names, even if the corresponding function wants one or more arguments. This is a standard convention.

1

Note: we've enumerated the operators in order from the highest (1) to the lowest (4) priorities. Try to work through the following expression: print(2 * 3 % 5) Both operators (* and %) have the same priority, so the result can be guessed only when you know the binding direction. How do you think? What is the result?

decimal floating comma

Now it's time to talk about another type, which is designed to represent and to store the numbers that (as a mathematician would say) have a non-empty deci____________ frac____________. Whenever we use a term like two and a half or minus zero point four, we think of numbers which the computer considers floa____________-point numbers. if your native language prefers to use a com____________ instead of a point in the number, you should ensure that your number doesn't contain any com____________ at all

10.0

Of course, you're always allowed to use parentheses, which can change the natural order of a calculation. In accordance with the arithmetic rules, subexpressions in parentheses are always calculated first. You can use as many parentheses as you need, and they're often used to improve the readability of an expression, even if they don't change the order of the operations. An example of an expression with multiple parentheses is here: print((5 * ((25 % 13) + 100) / (2 * 13)) // 2) Try to compute the value that's printed to the console. What's the result of the print() function?

e notation

On the other hand, it's not only points that make a float. You can also use the letter ____. When you want to use any numbers that are very large or very small, you can use scientific nota_______________.

zero

Operators: how not to divide As you probably know, division by ze______________ doesn't work. Do not try to: perform a division by ze______________ ; perform an integer division by ze______________ ; find a remainder of a division by ze______________ .

x = # hardcode your test data here x = float(x) # write your code here y = (3 * x ** 3) - (2 * x **2) + (3 * x) - 1 print("y =", y)

Take a look at the code in the editor: it reads a float value, puts it into a variable named x, and prints the value of a variable named y. Your task is to complete the code in order to evaluate the following expression: 3x3 - 2x2 + 3x - 1 The result should be assigned to y. Remember that classical algebraic notation likes to omit the multiplication operator - you need to use it explicitly. Note how we change data type to make sure that x is of type float. Keep your code clean and readable, and test it using the data we've provided, each time assigning it to the x variable (by hardcoding it). Don't be discouraged by any initial failures. Be persistent and inquisitive. x = # hardcode your test data here (first add 0) x = float(x) # write your code here print("y =", y) Input each sample input one by one and check the expected output Sample input x = 0 x = 1 x = -1 Expected Output y = -1.0 y = 3.0 y = -9.0

3E8 integer

Take, for example, the speed of light, expressed in meters per second. Written directly it would look like this: 300000000. To avoid writing out so many zeros, physics textbooks use an abbreviated form, which you have probably already seen: 3 x 108. It reads: three times ten to the power of eight. In Python, the same effect is achieved in a slightly different way - take a look: 3_______________8 The letter E (you can also use the lower-case letter e - it comes from the word exponent) is a concise record of the phrase times ten to the power of. Note: the exponent (the value after the E) has to be an inte_______________; the base (the value in front of the E) may be an inte_______________.

type literal memory

The characteristic of the numeric value which determines its kind, range, and application, is called the ty____________. If you encode a lite____________ and place it inside Python code, the form of the lite____________ determines the representation (ty____________) Python will use to store it in the me____________.

positional

The way in which we are passing the arguments into the print() function is the most common in Python, and is called the positi__________________ way (this name comes from the fact that the meaning of the argument is dictated by its posi________________

print function context

The word pri___________ that you can see here is a func___________ name. That doesn't mean that wherever the word appears it is always a function name. The meaning of the word comes from the con___________ in which the word has been used.

octal hexadecimal

There are two additional conventions in Python that are unknown to the world of mathematics. The first allows us to use numbers in an oct____________ representation. If an integer number is preceded by an 0O or 0o prefix (zero-o), it will be treated as an octal value. This means that the number must contain digits taken from the [0..7] range only. 0o123 is an oct____________ number with a (decimal) value equal to 83. The second convention allows us to use hexa____________numbers. Such numbers should be preceded by the prefix 0x or 0X (zero-x). 0x123 is a hexa____________ number with a (decimal) value equal to 291. The print() function can manage these values too.

truthfulness Boolean George algebra sensitivity

They're not as obvious as any of the previous ones, as they're used to represent a very abstract value - trut_______________. Each time you ask Python if one number is greater than another, the question results in the creation of some specific data - a Bool____________ value. The name comes from Geo________________ Boole (1815-1864), the author of the fundamental work, The Laws of Thought, which contains the definition of Bool______________ alge_____________- a part of alge___________________ which makes use of only two distinct values: True and False, denoted as 1 and 0. You cannot change anything - you have to take these symbols as they are, including case-sensi______________.

unary binary two minuend subtrahend

This is a great opportunity to present a very important distinction between un______________ and bin______________ operators. In subtracting applications, the minus operator expects tw______________ arguments: the left (a minue______________ in arithmetical terms) and right (a subtra______________). For this reason, the subtraction operator is considered to be one of the binary operators, just like the addition, multiplication and division operators. But the minus operator may be used in a different (unary) way - take a look at the last line of the snippet below: print(-4 - 4) print(4. - 8) print(-1.1) By the way: there is also a unary + operator. You can use it like this: print(+2)

invocation call parentheses arguments comma

To call a function (this process is known as function invo__________or function call), you need to use the function name followed by paren__________. You can pass argu__________ into a function by placing them inside the parentheses. You must separate argu__________ with a com__________

one instruction line empty prohibited across complex

Python's syntax is quite specific in this area. Unlike most programming languages, Python requires that there cannot be more than on___________ instruction in a li____________. A li__________ can be emp____________ (i.e., it may contain no instruction at all) but it must not contain two, three or more instructions. This is strictly prohi______________. Note: Python makes one exception to this rule - it allows one instruction to spread acro___________ more than one line (which may be helpful when your code contains comp__________ constructions).

division float

The divis____________________ operator is always a flo____________________, regardless of whether or not the result seems to be a flo____________________ at first glance: 1 / 2, or if it looks like a pure integer: 2 / 1

name value identifier dynamically declare

What does every Python variable have? a na______; a val_______ (the content of the container) Each variable must have a unique name - an iden_____________. Python is a dynam_____________-typed language, which means you don't need to decl_____________ variables in it.

arguments converts readable output device console

What is the effect the print() function causes? The effect is very useful and very spectacular. The function: takes its argu______________ (it may accept more than one argu____________ and may also accept less than one argu___________) conv____________ them into human-read_____________ form if needed (as you may suspect, strings don't require this action, as the string is already readable) and sends the resulting data to the out_____________ devi_____________ (usually the cons_____________ ); in other words, anything you put into the print() function will appear on your screen.

11

What is the output of the following snippet? a = '1' b = "1" print(a + b)

1.0 2 * b = 6a = 6 → 6 / 6 = 1.0

What is the output of the following snippet? a = 6 b = 3 a /= 2 * b print(a)

1e-22

When you run this literal through Python: print(0.0000000000000000000001) this is the result: Python always chooses the more economical form of the number's presentation, and you should take this into consideration when creating literals.

compound x *= 2 sheep += 1

You can also use comp______________ assignment operators (shortcut operators) to modify values assigned to variables For example, if we need to calculate a series of successive values of powers of 2, we may use a piece like this: x = x * 2 You may use an expression like this if you can't fall asleep and you're trying to deal with it using some good, old-fashioned methods: sheep = sheep + 1 Python offers you a shortened way of writing operations like these, which can be coded as follows: x ___ = 2 sheep ____ = 1

code executed data

You can imagine that the quotes say something like: the text between us is not co__________________. It isn't intended to be exe__________________, and you should take it as is. Almost anything you put inside the quotes will be taken literally, not as code, but as da_______________. Try to play with this particular string - modify it, enter some new content, delete some of the existing content.

string order previous

each print() invocation contains a different str____________, as its argument and the console content reflects it - this means that the instructions in the code are executed in the same ord___________ in which they have been placed in the source file; no next instruction is executed until the previ_____________ one is completed (there are some exceptions to this rule, but you can ignore them for now)

2

var = 1 print(var) var = var + 1 print(var) Answer?

imported 69

Built-in functions, contrary to user-defined functions, are always available and don't have to be impor__________. Python 3.8 comes with ___(#2) built-in functions.

decimal front after

But don't forget this simple rule - you can omit zero when it is the only digit in fro_____________ of or aft______________ the dec_______________ point. In essence, you can write the value 0.4 as: .4 For example: the value of 4.0 could be written as: 4.

disable

Comments are very important. They are used not only to make your programs easier to understand, but also to disa____________ those pieces of code that are currently not needed (e.g., when you need to test some parts of your code only, and ignore other).

instructions command task backslash next character meaning

Computer programs are collections of instru____________. An instru____________ is a com____________ to perform a specific ta____________ when executed, e.g., to print a certain message to the screen. In Python strings the bac____________ (\) is a special character which announces that the nex____________ chara____________ has a different mean____________, e.g., \n (the newline character) starts a new output line.

double

If you want to put just one backslash inside a string, don't forget its escaping nature - you have to dou_____________ it

parentheses arguments parentheses

In spite of the number of needed/provided arguments, Python functions strongly demand the presence of a pair of paren__________________ - opening and closing ones, respectively. If you want to deliver one or more argu__________________ to a function, you place them inside the paren__________________ . If you're going to use a function which doesn't take any argu__________________ , you still have to have the paren__________________ .

integers float

It's possible to formulate the following rules based on this result: when both ** arguments are integ____________________, the result is an integ____________________, too; when at least one ** argument is a flo____________________, the result is a flo____________________, too.

This will work as intended: print("I like \"Monty Python\"")

Let's assume that we want to print a very simple message saying: I like "Monty Python" How do we do it without generating an error? There are two possible solutions. The first is based on the concept we already know of the escape character, which you should remember is played by the backslash. The backslash can escape quotes too. A quote preceded by a backslash changes its meaning - it's not a delimiter, but just a quote. Use 2 backslashes for I like "Monty Python"

binary numbers integers fractional floating fractional

Perhaps you've heard of the bin____________ system, and know that it's the system computers use for storing num____________, and that they can perform any operation upon them. inte____________, that is, those which are devoid of the fract____________ part; and floa____________-point numbers (or simply floats), that contain (or are able to contain) the fract____________ part.

Positional location word identify

Posit____________ arguments are the ones whose meaning is dictated by their posit____________, e.g., the second argument is outputted after the first, the third is outputted after the second, etc. Keyword arguments are the ones whose meaning is not dictated by their loca____________, but by a special wor____________ (key____________) used to identify them.

length languages

Python does not impose restrictions on the len____________ of variable names, but that doesn't mean that a long variable name is always better than a short one. Moreover, Python lets you use not only Latin letters but also characters specific to langu________________ that use other alphabets.

binding computations equal left right

The bind_______________ of the operator determines the order of comput_______________ performed by some operators with equ_______________ priority, put side by side in one expression. Most of Python's operators have le_______________-sided binding, which means that the calculation of the expression is conducted from le_______________ to rig_______________. This simple example will show you how it works. Take a look: print(9 % 6 % 2)

formatting between outputted print

The end and sep parameters can be used for forma____________ the output of the print() function. The sep parameter specifies the separator betw____________ the output____________ arguments (e.g., print("H", "E", "L", "L", "O", sep="-"), whereas the end parameter specifies what to pri____________ at the end of the pri____________ statement.

invocation

The function name (print in this case) along with the parentheses and argument(s), forms the function invoc_____________.

keyword position

The mechanism is called ke___________ arguments. The name stems from the fact that the meaning of these arguments is taken not from its location (posi________) but from the special word (ke_____________) used to identify them.

modulo remainder 3.0

The operator is sometimes called modu______________ in other programming languages. The result of the operator is a remain______________ left after the integer division. In other words, it's the value left over after dividing one value by another to produce an integer quotient. Take a look at the snippet - try to predict its result and then run it: print(14 % 4) As you can see, the result is two. This is why: 14 // 4 gives 3 → this is the integer quotient; 3 * 4 gives 12 → as a result of quotient and divisor multiplication; 14 - 12 gives 2 → this is the remainder. print(12 % 4.5) = ?

print('I like "Monty Python"')

The second solution may be a bit surprising. Python can use an apostrophe instead of a quote. Either of these characters may delimit strings, but you must be consistent. If you open a string with a quote, you have to close it with a quote. If you start a string with an apostrophe, you have to end it with an apostrophe. Use the apostrophe with quotes for I like "Monty Python"

separator empty string

We've said previously that the print() function separates its outputted arguments with spaces. This behavior can be changed, too. The keyword argument that can do this is named se_______ (like separ________________). Note: the se______________ argument's value may be an emp______________ stri______________________, too. Try it for yourself.

legal data requirements function effect result code resumes

What happens when Python encounters an invocation like this one below? function_name(argument) First, Python checks if the name specified is leg_______________ (it browses its internal da____________ in order to find an existing function of the name; if this search fails, Python aborts the code); second, Python checks if the function's requi___________________ for the number of arguments allows you to invoke the function in this way (e.g., if a specific function demands exactly two arguments, any invocation delivering only one argument will be considered erroneous, and will abort the code's execution); third, Python leaves your code for a moment and jumps into the func_________________ you want to invoke; of course, it takes your argument(s) too and passes it/them to the function; fourth, the function executes its co_________________ , causes the desired eff_________________ (if any), evaluates the desired res_________________ (s) (if any) and finishes its task; finally, Python returns to your code (to the place just after the invocation) and resu___________________ its execution.

-0.5 0.5 0 -1

What is the output of the following snippet? print((-2 / 4), (2 / 4), (2 // 4), (-2 // 4))

-2 2 512

What is the output of the following snippet? print((2 % -4), (2 % 4), (2 ** 3 ** 2))

added modules write names

Where do the functions come from? They may come from Python itself; the print function is one of this kind; such a function is an ad___________ value received together with Python and its environment (it is built-in); you don't have to do anything special (e.g., ask anyone for anything) if you want to make use of it; they may come from one or more of Python's add-ons named mod___________; some of the mod___________ come with Python, others may require separate installation - whatever the case, they all need to be explicitly connected with your code (we'll show you how to do that soon); you can wr___________ them yourself, placing as many functions as you want and need inside your program to make it simpler, clearer and more elegant. Of course, if you're going to make use of any already existing function, you have no influence on its na___________, but when you start writing your own functions, you should consider carefully your choice of na___________.

separate

You can use sep="\n" to execute the variables on separ_____________ lines.

hierarchy of priorities before

You surely remember that you should first multiply 3 by 5 and, keeping the 15 in your memory, then add it to 2, thus getting the result of 17. The phenomenon that causes some operators to act before others is known as the hier_______________ of prior_______________. Python precisely defines the priorities of all operators, and assumes that operators of a larger (higher) priority perform their operations bef_______________ the operators of a lower priority.

reserved predefined

['False', 'None', 'True', 'and', 'as', 'assert', 'break', 'class', 'continue', 'def', 'del', 'elif', 'else', 'except', 'finally', 'for', 'from', 'global', 'if', 'import', 'in', 'is', 'lambda', 'nonlocal', 'not', 'or', 'pass', 'raise', 'return', 'try', 'while', 'with', 'yield'] They are called keywords or (more precisely) rese__________________្keywords. They are reserved because you mustn't use them as names: neither for your variables, nor functions, nor any other named entities you want to create. The meaning of the reserved word is pred________________, and mustn't be changed in any way.

keyword argument value position

a ke____________ argument consists of three elements: a ke_____________ identifying the argu_________________ (end here); an equ__________ sign (=); and a valu______________ assigned to that argument; any ke_______________ argu______________ have to be put after the la_______________ posi_____________ argu_______________ (this is very important)

argument space

a print() function invoked with more than one argu______________ outputs them all on one line; the print() function puts a spa__________________ between the outputted argu_________________ on its own initiative.

effect evaluate a value result

cause some eff___________ (e.g., send text to the terminal, create a file, draw an image, play a sound, etc.); this is something completely unheard of in the world of mathematics; evalu___________ a val___________ (e.g., the square root of a value or the length of a given text) and return it as the function's res___________; this is what makes Python functions the relatives of mathematical concepts.

i += 2 * j var /= 2 rem %= 10 j -= (i + var + rem) x **= 2

i = i + 2 * j ⇒ i ____ = 2 * j var = var / 2 ⇒ var _____ = 2 rem = rem % 10 ⇒ rem ______ = 10 j = j - (i + var + rem) ⇒ j ______ = (i + var + rem) x = x ** 2 ⇒ x ______ ______ = 2

print("Programming","Essentials","in", sep="***", end="...") print("Python")

print("Programming","Essentials","in") print("Python") Modify the first line of code in the editor, using the sep and end keywords, to match the expected output. Use the two print() functions in the editor. Don't change anything in the second print() invocation. Expected output Programming***Essentials***in...Python

literal encode

A lite____________ is data whose values are determined by the literal itself. And this is the clue: 123 is a liter____________, and c is not. You use literals to encode data and to put them into your code.

remark comment

A rem___________ inserted into the program, which is omitted at runtime, is called a com___________.

integer floating

Look at these two numbers: 4 4.0 You may think that they are exactly the same, but Python sees them in a completely different way. 4 is an integer number, whereas 4.0 is a floating-point number.

operations evaluations

No wonder then, that from now on, you'll utilize print() very intensively to see the results of your opera_____________ and evalu_____________ .

delimited quotes

Python strings are delim____________ with quo______________, e.g., "I am a string" (double quotes), or 'I am a string, too' (single quotes).

end

The print() function has two keyword arguments that you can use for your purposes. The first of them is named en_______.

My_name_is*Monty*Python.*

print("My", "name", "is", sep="_", end="*") print("Monty", "Python.", sep="*", end="*\n") What is the output?

operator

An oper____________________ is a symbol of the programming language, which is able to operate on the values. For example, just as in arithmetic, the + (plus) sign is the operator which is able to add two numbers, giving the result of the addition. Not all Python operators are as obvious as the plus sign, though, so let's go through some of the operators available in Python, and we'll explain which rules govern their use, and how to interpret the operations they perform. We'll begin with the operators which are associated with the most widely recognizable arithmetic operations: +, -, *, /, //, %, **

letter space

And now for some incorrect names: 10t (does not begin with a let___________), Exchange Rate (contains a spa___________)

types

Any. We'll show you soon that print() is able to operate with virtually all ty___________ of data offered by Python. Strings, numbers, characters, logical values, objects - any of these may be successfully passed to print()

effect result argument number zero

As we said before, a function may have : an eff___________; a res___________. There's also a third, very important, function component - the argu___________(s). Mathematical functions usually take one argument, e.g., sin(x) takes an x, which is the measure of an angle. Python functions, on the other hand, are more versatile. Depending on the individual needs, they may accept any nu______________ of arguments - as many as necessary to perform their tasks. Note: any number includes ze_____________ - some Python functions don't need any argument.

new

As you can see, the empty print() invocation is not as empty as you may have expected - it does output an empty line, or (this interpretation is also correct) its output is just a n__________-line.

characters positional arguments

As you can see, the end keyword argument determines the chara_____________ the print() function sends to the output once it reaches the end of its posit_____________ argum_____________. The default behavior reflects the situation where the end keyword argum_____________ is implicitly used in the following way: end="\n".

expression combination operators symbols or keywords unary one two subexpressions in parentheses first exponentiation right

1. An expre_______________ is a combin_______________ of values (or variables, operators, calls to functions - you will learn about them soon) which evaluates to a value, e.g., 1 + 2. 2. Oper_______________ are special symb_______________ or keyw_______________ which are able to operate on the values and perform (mathematical) operations, e.g., the * operator multiplies two values: x * y. 3. Arithmetic operators in Python: + (addition), - (subtraction), * (multiplication), / (classic division - always returns a float), % (modulus - divides left operand by right operand and returns the remainder of the operation, e.g., 5 % 2 = 1), ** (exponentiation - left operand raised to the power of right operand, e.g., 2 ** 3 = 2 * 2 * 2 = 8), // (floor/integer division - returns a number resulting from division, but rounded down to the nearest whole number, e.g., 3 // 2.0 = 1.0) 4. A una_______________ operator is an operator with only o_______________ operand, e.g., -1, or +3. 5. A bin_______________ operator is an operator with tw_______________operands, e.g., 4 + 5, or 12 % 5. 6. Some operators act before others - the hierarchy of priorities: unary + and - have the highest priority then: **, then: *, /, and %, and then the lowest priority: binary + and -. 7. Subexp_______________ in paren_______________ are always calculated first, e.g., 15 - 1 * (5 * (1 + 2)) = 0. 8. The expone_______________ operator uses rig_______________-sided binding, e.g., 2 ** 2 ** 3 = 256.

notations fixed binary Octal hexadecimal fractional escape None absence

1. Literals are nota______________ for representing some fix______________ values in code. Python has various types of literals - for example, a literal can be a number (numeric literals, e.g., 123), or a string (string literals, e.g., "I am a literal."). 2. The bin______________ system is a system of numbers that employs 2 as the base. Therefore, a binary number is made up of 0s and 1s only, e.g., 1010 is 10 in decimal. Oct______________ and hexadec______________ numeration systems, similarly, employ8 and 16 as their bases respectively. The hexad______________ system uses the decimal numbers and six extra letters. 3. Integers (or simply ints) are one of the numerical types supported by Python. They are numbers written without a fracti______________ component, e.g., 256, or -1 (negative integers). 4. Floating-point numbers (or simply floats) are another one of the numerical types supported by Python. They are numbers that contain (or are able to contain) a fracti______________ component, e.g., 1.27. 5. To encode an apostrophe or a quote inside a string you can either use the esc______________ character, e.g., 'I\'m happy.', or open and close the string using an opposite set of symbols to the ones you wish to encode, e.g., "I'm happy." to encode an apostrophe, and 'He said "Python", not "typhoon"' to encode a (double) quote. 6. Boolean values are the two constant objects True and False used to represent truth values (in numeric contexts 1 is True, while 0 is False. EXTRA There is one more, special literal that is used in Python: the No______________ literal. This literal is a so-called No______________Type object, and it is used to represent the absence of a value.

prohibited underscores

11,111,111, or like this: 11.111.111, or even like this: 11 111 111 Python doesn't accept things like these. It's prohi____________. What Python does allow, though, is the use of under____________ in numeric literals.* Therefore, you can write this number either like this: 11111111, or like that: 11_111_111. And how do we code negative numbers in Python? As usual - by adding a minus. You can write: -11111111, or -11_111_111

slash fractional rounded

A // (double sla______________) sign is an integer divisional operator. It differs from the standard / operator in two details: its result lacks the fract______________ part - it's absent (for integers), or is always equal to zero (for floats); this means that the results are always roun______________; it conforms to the integer vs. float rule. Example below and see the results: print(6 // 3) print(6 // 3.) print(6. // 3) print(6. // 3.)

6.62607E-34

A physical constant called Planck's constant (and denoted as h), according to the textbooks, has the value of: 6.62607 x 10-34. How should you write it into Python? Note: the fact that you've chosen one of the possible forms of coding float values doesn't mean that Python will present it the same way. Python may sometimes choose different notation than you.

expressions literals

Data and operators when connected together form expres____________________. The simplest expression is a lite____________________ itself.