Strings

6. Write a function that reverses its string argument.

def reverse(astring):
     bstring = astring[None:None:-1]
     return bstring

print reverse("Adrian")
print reverse("silshack")

Output

nairdA
kcahslis

7. Write a function that mirrors its argument.

def mirror(mystr):
    newstr = mystr[:len(mystr)][::-1]
    return mystr+newstr

print mirror("Adrian")
print mirror("Ogletree")

Output

AdriannairdA
OgletreeeertelgO

11. Write a function that removes the first occurrence of a string from another string.

Output

12. Write a function that removes all occurrences of a string from another string.

Output

Lists

7. Write a function to count how many odd numbers are in a list.

def count_odd(list):
    #Make a counting variable
    odd_count = 0
    for number in list:
        #Is it odd?
        if number % 2 == 1:
            odd_count += 1
    return odd_count

print (count_odd([1, 3, 5, 4]))

Output

3

8. Sum up all the even numbers in a list.

def sum_even(list):
    sum = 0
    for i in list:
        if i % 2 == 0:
            sum = sum + i
    return sum

print (sum_even([2, 8, 7, 1000]))

Output

1010

9. Sum up all the negative numbers in a list.

Once I figured out #8, this was pretty simple. ``` def sum_negative(list): sum = 0 for i in list: if i < 0: sum = sum + i return sum

print (sum_negative([-1, 0, 10, -5, -11, 8])) ```

Output

-17

14. Write a function replace(s, old, new) that replaces all occurences of old with new in a string s.

Output