Previous: Types

The blocks

A block is a series of actions. In python it is defined by the level of tabulation.

Conditional blocks

Often, you have to perform one action or another depending on the value of a variable.

In python, the structure of conditional blocks are:

Instructions if true condition


Instructions if true condition
Instructions if false condition

important: Note the use of the :, in python it is essential to put it at the end of the first line of the block :)

note: we will use the print function to display in the terminal :)

Small example:

ta_note_en_maths = 9
if ta_note_en_maths <10:
print ("You missed")
print ("Congratulations")


Often, we realize that we must perform the same action several times. It would be a shame to rewrite the same code several times, that's why loops exist.

There are two types of loops, it depends on whether you know when it stops or not.

FOR loop

The for loop is important to understand and master. It allows you to repeat an action n times, or to browse a list in python.

You used it in your lessons to repeat an action n times, but it also allows you to browse a list of elements:

list = [1, 4, 5, 6, 0]
for element in list:
print (element)

Above, the variable element will take the value in the list at each loop.

while loop

The while loop, translated into a loop as much as in French :), is a loop to use when we don't know how many times we will do our processing.

For example, if we wait for the user to type the word: "StarLight".

user_entry = "NotStartLight" # I initialize the variable
while userinput! = "StarLight": # as long as the user input is not StarLight
user_entry = input () # we ask the user to type something
print (user_entry) # We display the user input

This above program runs until the user has entered the requested word :).

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