We continue to learn the programming language. Let’s move on to chapter 4 of the book: Michael Dawson “Python Programming”, 2014 (Michael Dawson “Python Programming for the Absolute Beginner”, 3rd Edition), where we will study loops with the for () operator, introducing constants into code, slices and tuples, working with sequences on the example of strings with the operators len(), range(), in, jumble(), etc.

Summary of chapter 4 with examples of programs I wrote:

Cycles (loops) for

We already know loops with the while statement, and have even done a lot of tasks. Remember, there is a control variable introduced before the loop, which is then used in the condition, which in turn is tested for truth every round of the loop. So with the for loop, things are a little different. Читать →

The if statement (if) is used to set conditions (if so, then…), for example:

cat_say = ‘mew’

if cat_say = ‘mew’ of cat_say = ‘myavki’:

….print(‘Dear, cat! Here’s your food!’)

Important: when using if conditions, you need to write double equals and put a colon at the end of the expression to show the end of the condition; before the rest of the code related to the condition, and print is indented with a tab (or 4 spaces).

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We continue to learn programming. After the second chapter in the book: Michael Dawson “We Program in Python”, 2014 (Michael Dawson “Python Programming for the Absolute Beginner”, 3rd Edition), where I studied the features of working with text in the Python programming language, tasks were offered. Let’s do them together. I will give my solution, and you write your options in the comments.

1) Come up with two lists: valid and invalid variable names. Explain why each of the names is valid or not valid, respectively. Then come up with two more lists—of “good” and “bad” valid names—and explain your choice.

Valid variable names: name, price, password, age, size (these can be any words that are not reserved in the programming language for functions / operators)

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We continue to learn programming. After the second chapter in the book: Michael Dawson “We Program in Python”, 2014 (Michael Dawson “Python Programming for the Absolute Beginner”, 3rd Edition), where I studied the features of working with text in the Python programming language, tasks were offered. Let’s do them together. I will give my solution, and you write your options in the comments.

1) Learn how to trigger a bug: Interactively enter the name of your favorite ice cream brand. Then fix the error and create a command that will correctly display the name on the screen this type of ice cream.

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There are several data types in the Python programming language, for example:

• integers int(x), for example, 1-2-3-4;
• fractional numbers float(x), for example, 1.0-2.0-3.5;
• str(x) strings, which can contain text and other characters.

The input() function has already been discussed earlier, this function allows the user to enter data into the program, this data can be further used.

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The very first text operations and basic information about Python that helps you start programming right away:

# Comments

Delimiters ” or “” and escaping characters ’ and ”

print(‘Hello world’) – newline

end=’…’ – next print will be glued

escape sequences:

a – system speaker

n – newline (empty line)

t – tab type indent

+ string concatenation without delimiter

* repeat lines without delimiter

continuation of a line of code on the next line

input(‘Press Enter to exit’)

Basic mathematical operators (+,-,*,/,//,%).

Compound assignment statements

String methods (applied to a string with text): I am cat

.upper() I Am CAT

.lower() i am cat

.title() I Am Cat

.replace(old,new,max number of replacements) replaces the old text with the new one

.swapcase() reverse case i Am Cat

.capitalize() the first letter is capital, the rest are lowercase I am cat

.strip() string without intervals Iamcat

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