#### Exercise 72

Write a function which takes an element x and a list L as a parameter, and returns the list of positions of x in L. The function must return the empty list if the element x does not appear in the list L.

#### Solution

`def positions (x, L):`

# initialization of the list of positions of x in L

LPositions = []

for i in range (0, len (L)):

if L [i] == x:

LPositions.append (i)

return LPositions

#Example

x = 3

y = 5

L = [2, 3, 7, 3, 11, 9, 3, 4]

print (positions (x, L)) # the output [1, 3, 6]

print (positions (y, L)) # the output: []

**Younes Derfoufi**

my-courses.net

my-courses.net