---- define a function ----

def double(sequence): #this functions creates a sequence of elements
    result = [] #the result is an array of elements
    for element in sequence: #this is pretty literal, for each of the elements inside the sequence
        result = result + [element*2] #the result-array is the given array with its elements*2
    return result

double([2, 3, 5])

[4, 6, 10]

double([-53])

[-106]

double([334253, 235, 653, (-23*5)])

[668506, 470, 1306, -230]

double([])

[]

double() #it's gonna be an error

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
/tmp/ipykernel_4283/4249856066.py in <module>
----> 1 double() #it's gonna be an error

TypeError: double() missing 1 required positional argument: 'sequence'

----check your expectations----

def tip():
    print('check your expectations')

tip()

check your expectations

x = [1,2,3]

double(x)

[2, 4, 6]

x

[1, 2, 3]

this is a function which take all the elements of an array and multiply them by 2, withouth modifying the original array

def double(sequence): result = [] for element in sequence: result = result + [element*2] return result

double(9)

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
/tmp/ipykernel_4283/3171148046.py in <module>
----> 1 double(9)

/tmp/ipykernel_4283/2190915392.py in double(sequence)
      1 def double(sequence):
      2     result = []
----> 3     for element in sequence:
      4         result = result + [element*2]
      5     return result

TypeError: 'int' object is not iterable

double([7,2,4],[4])

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
/tmp/ipykernel_4283/2869834229.py in <module>
----> 1 double([7,2,4],[4])

TypeError: double() takes 1 positional argument but 2 were given

---------- FREE PROJECT 5-1 ----------

def triple(sequence):
    result=[]
    for element in sequence:
        result=result+[element*3]
    return result

triple([1,2,4])

[3, 6, 12]

def repeat(sequence): #standardization of symbols into commodity
    result=[]
    for element in sequence:
        result = result + ['1$']
    return result

repeat([3,6])

['1$', '1$']

repeat([1,2,4])

['1$', '1$', '1$']

def addone(sequence):
    result = []
    for a in sequence:
        result = result + [a+1]
    return result
        
    

addone([3,7,5])

[4, 8, 6]

addone([0])

[1]

addone([])

[]

def total(sequence):
    tot = 0
    for element in sequence:
        tot = tot + element
    return tot

total([4, 5, 6, 7])

22