Ludium - Learn by Doing

Total the Values That Convert

Assume you are given a list named values whose elements are supposed to be numbers but might be anything at all — numeric strings, junk strings, even None.

Write a function total_convertible(values) that returns the running total of every element that float(...) accepts, quietly skipping any element that makes the conversion fail. The result is always a float, and a list where nothing converts (including the empty list) totals 0.0.

You may not test the type of an element before adding it — attempt the conversion and recover when it goes wrong.

total_convertible([3, '4.5', 'hello', '10'])  ->  17.5
total_convertible([1, None, '2'])             ->  3.0
total_convertible(['a', 'b'])                 ->  0.0

def total_convertible(values):
    """Return the sum, as a float, of every element of the list `values`
    that can be converted to a float. Elements that cannot be converted are
    skipped. Returns 0.0 when nothing converts."""
    pass

def total_convertible(values):
    """Return the sum, as a float, of every element of the list `values`
    that can be converted to a float. Elements that cannot be converted are
    skipped. Returns 0.0 when nothing converts."""
    pass

Scratchpad— run any Python to test ideas

# Scratchpad — run any Python here to test ideas.
# Anything you write below stays separate from the problem's tests.

print("hello, world")

# Scratchpad — run any Python here to test ideas.
# Anything you write below stays separate from the problem's tests.

print("hello, world")

Python runtime ready in a moment

Visible tests · 2Examples — click to expand

mixed numbers and strings total 17.5

nothing convertible totals 0.0

Hidden tests · 4Bodies hidden — pass/fail only

Hidden test 1

Hidden test 2

Hidden test 3

Hidden test 4

Total the Values That Convert

Assume you are given a list named values whose elements are supposed to be numbers but might be anything at all — numeric strings, junk strings, even None.

You may not test the type of an element before adding it — attempt the conversion and recover when it goes wrong.

total_convertible([3, '4.5', 'hello', '10'])  ->  17.5
total_convertible([1, None, '2'])             ->  3.0
total_convertible(['a', 'b'])                 ->  0.0

def total_convertible(values):
    """Return the sum, as a float, of every element of the list `values`
    that can be converted to a float. Elements that cannot be converted are
    skipped. Returns 0.0 when nothing converts."""
    pass

def total_convertible(values):
    """Return the sum, as a float, of every element of the list `values`
    that can be converted to a float. Elements that cannot be converted are
    skipped. Returns 0.0 when nothing converts."""
    pass

Scratchpad— run any Python to test ideas

# Scratchpad — run any Python here to test ideas.
# Anything you write below stays separate from the problem's tests.

print("hello, world")

# Scratchpad — run any Python here to test ideas.
# Anything you write below stays separate from the problem's tests.

print("hello, world")

Python runtime ready in a moment

Visible tests · 2Examples — click to expand

mixed numbers and strings total 17.5

nothing convertible totals 0.0

Hidden tests · 4Bodies hidden — pass/fail only

Hidden test 1

Hidden test 2

Hidden test 3

Hidden test 4

Coding challenges on exceptions and assertions

Total the Values That Convert

Coding challenges on exceptions and assertions

Total the Values That Convert