Stripping '$'-sign from sales list

Question

Why am I unable to strip '$' in the first method of code however I am able to strip in the second method?

Method 1

sales = ['$1.21', '$7.29', '$12.52', '$5.13', '$20.39', '$30.82', '$1.85', '$17.98', '$17.41', '$28.59']

for element in sales:
 element.strip('$')

 print(element)

Method 2

sales = ['$1.21', '$7.29', '$12.52', '$5.13', '$20.39', '$30.82', '$1.85', '$17.98', '$17.41', '$28.59']

for element in sales:

 print(element.strip('$'))

Answer 1

You need to assign the variable in the for loop and use indexing if you want to change the original list:

sales = ['$1.21', '$7.29', '$12.52', '$5.13', '$20.39', '$30.82', '$1.85', '$17.98', '$17.41', '$28.59']

for x in range(len(sales)):
    sales[x] = sales[x].strip('$')
    print(sales[x])

Answer 2

It seems like you'd like to treat sales as a numeric variable

sales = ['$1.21', '$7.29', '$12.52', '$5.13', '$20.39', '$30.82', '$1.85', '$17.98', '$17.41', '$28.59']


sales = [float(element.strip('$')) for element in sales]

Then you could either print it or sum it

print("total sales: {t:.2f}".format(t=sum(sales)))

Answer 3

str.strip method does not modify given string, instead it returns the result as it is specified in official documentation.

Return a copy of the string with the leading and trailing characters removed.

Since element.strip('$') returns result instead of modifying element this code does nothing.

Answer 4

To convert it into cents (don't ever do currency work with floats since floats are imprecise, you can do this:

sales_in_cents =  [int(element.strip('$').replace('.','')) for element in sales]

To show the total in $...

print(f'Total sales : {sum(sales_in_cents)/100:0.2f}'

Do all of your calculations (including your sums) with cents and convert to $ (by dividing by 100 only when you need to do so.