3. File construction

• Lines that start with “#” are called comments

• They are intended to be read by humans and Python ignores them

• Python skips all text from the “#” to the end of the line

# File chaos.py
# A program that illustrates the Chaos Theory

• x is an example of a variable

• We will assign a value to x that can be referred to later

• The message in quotes will be displayed and the response will be stored in x

x = eval(input("Enter a number between 0 and 1:"))

• There are loop or cycle commands such as the for command

• A loop or cycle is used to repeat a block of code several times

• In this example, the following block will be repeated 10 times

for i in range(10):

• We call indentation to the spaces at the beginning of the line

• In Python, indentation delimits the block that will be executed

• The calculation 3.9 * x * (1-x) will be performed on the CPU and assigned to the variable x

3.1. Result

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# File chaos.py

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# A program that illustrates the Chaos Theory

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print("This program illustrates chaotic behavior.")

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x = eval(input("Enter a number between 0 and 1:"))

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for i in range(10):

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    x = 3.9 * x * (1 - x)

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    print("%2.3f" % x)

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​

Activity: 3.1.1 ActiveCode (ac_l38_3_en)

• The chaos program returns very different values, even when the input is similar.

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