Change type of elements in a list by column

[snippsat]

Here a hint for integer convert.

>>> my_list = [['john', '1', '2:00pm'], ['becky', '2', '3:15pm'], ['tom', '3', '3:20pm']]
>>> [[int(x) for x in lst] for lst in my_list]

Error:
Traceback (most recent call last):
 File "<string>", line 301, in runcode
 File "<interactive input>", line 1, in <module>
 File "<interactive input>", line 1, in <listcomp>
 File "<interactive input>", line 1, in <listcomp>
ValueError: invalid literal for int() with base 10: 'john

Now it try to convert all element in the nested list.
Can wirte a helper function that catch ValueError

def try_int(x):
    try:
        return int(x)
    except ValueError:
        return x

Now try again:

>>> [[try_int(x) for x in lst] for lst in my_list]
[['john', 1, '2:00pm'], ['becky', 2, '3:15pm'], ['tom', 3, '3:20pm']]

3rd element to date.time?

Do you know how to this,like with only 1 value '3:20pm'?