Python for beginners

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VARIABLES

• Introduction to the objects string & list with their different attributes
• uses the shell or editor

# USING STRINGS

A string is a chain of characters / text and can contain any type of characters

A string is defined by " "

Write text using STRING

>>> print("La Cambre")

• • Exercise: Write your name

>>> ...

Adding text

>>> print("Brussels"+"Paris")

>>> print("Brussels "+"Paris")

• • Exercise: Write your address

Composing a sentence

>>> print("Paris", "to", "London", "via", "Brussels")

>>> print("Paris to London via Brussels")

• • Exercise: Write your favourite expression

Multiply

>>> print(3*3)

>>> 3 * "algolit" + " in Brussels"

• • Exercise: Write 'I write the alphabet' 3 times.

Note: there are always different possible solutions

Write a string as a variable

• • Avoids having to retype your string each time you use it
  • You can change values at any time of the writing process

>>> letter = "a"

>>> print(letter)

>>> word = "algolit"

>>> print(word)

>>> sentence = "I learn to read and write again in Python."

>>> print(sentence, letter)

• • Exercise: Print your letter, word, sentence

Add punctuation

>>> print(letter + " " + word + " " + sentence + ".")

>>> print(letter + "! " + word + "? " + sentence + ".")

>>> letter = "i"

>>> print letter + "! " + word + "? " + sentence + "."

• • Exercise: change content of one of variables, over and over, see how result changes

Calculate!

• • the length of the string

>>> print(len(letter)) >>> print(len(word)) >>> print(len(sentence)) >>> print(len(word))+2)

• • and more

a_number = len(word)+2 print(a_number) a_number += 3 print(a_number)

• • Exercise: Compose a sentence word by word, specifying each word as a variable. The length of the sentence is 20.

What you've learned

• variable
• value
• assignment operator (=)
• difference between variables and values
• integers
• print()
• len()