Title: Programming Logic
Slug: 03-s6-step-3
Date: 2020-11-01 12:02
Summary: Loops, if/else statements, variables and more.

<!-- > People, things, events are "programmed", one speaks of "inputs" and "outputs", of feedback loops, variables, parameters, processes, and so on, until eventually all contact with concrete situations is abstracted away.[^weizenbaum] -->
<!-- [^weizenbaum]: Weizenbaum, Joseph "Computer Power and Human Reason, From Judgement to Calculation" (1976) -->

As bots are written in code, they are based on the features and constraints of *programming logic*.

To unpack this term, we will look at how the following elements are operating, specifically in the programming language Python:

* data objects
* loops
* if/else statements
* variables

### Data Objects

How to store data?

Lists

```
agents = ['bot', programmer', 'user', 'moderator', 'server', 'regulator']
colors = ['red', 'magenta', 'yellow', 'blue', 'purple', 'green']
objects = ['apple', 'book', 'cable'] 
```

Dictionaries

```
vocabulary = { 
	'welcome' : 'Hello, how are you doing?', 
	'disagreement' : 'That makes no sense to me.', 
	'greeting' : 'Thanks for this, bye!' 
}
```

### Loops

A loop is an element in programming that allows you to execute a single line of code multiple times. It is a central figure in automatising a task that is repetitive. 

By using for example a `range()` loop, you can ask the program to execute a command `x` many times. In the following example, the `print()` command is asked to return the word `bot` as many times as the loop is iterating.

```
for x in range(5):
	print('bot' * x)

> bot
> botbot
> botbotbot
> botbotbotbot
> botbotbotbotbot
```

Another type of loop is the `while` loop, which allows to repeat a command for an infinite number of times. This type of loop can be stopped by a manual interruption of the programmer, usually by typing a specific key-combination, such as `CTRL+D`.

```
while True:
	print('bot')

> bot
> bot
> bot
> bot
> bot
```

Other loops, such as the `for` loop, are useful to iterate over a specific set of items. If you would like to write a bot that would, for example, post a message of each sentence of a book, you could loop over all the sentences and `print()` them one by one.

```
sentences = open('book.txt').readlines()

for sentence in sentences:
	print('sentence')

> This is the first sentence.
> This is the second sentence.
> This is the third sentence.
```

### if/else statements

A next element in writing your bot could include the description of specific behavior at specific moments. If/else statements are used to trigger certain commands `if` a specific condition is met, or `else` execute an alternative command. 

```
for x in range(5):
	if x < 3:
		print('Counting ... ' + str( x ))
	else:
		print('Nearing to the end ... ' + str( x ))

> Counting ... 0
> Counting ... 1
> Counting ... 2
> Nearing to the end ... 3
> Nearing to the end ... 4
```

### Variables


## Footnotes