How to convert list of intable strings to int

Question

In Python, I want to convert a list of strings:

l = [\'sam\',\'1\',\'dad\',\'21\']

and convert the integers to integer types like this:

Answer 1

• Use a list comprehension to validate the numeracy of each list item.
• str.isnumeric won't pass a negative sign
  • Use str.lstrip to remove the -, check .isnumeric, and convert to int if it is.
  • Alternatively, use str.isdigit in place of .isnumeric.

Keep all values in the list

l = ['sam', '1', 'dad', '21', '-10']

t = [int(v) if v.lstrip('-').isnumeric() else v for v in l]

print(t)

>>> ['sam', 1, 'dad', 21, -10]

Remove non-numeric values

l = ['sam', '1', 'dad', '21', '-10']

t = [int(v) for v in t if v.lstrip('-').isnumeric()]

print(t)

>>> [1, 21, -10]

Nested list

l = [['aa', '2'], ['bb', '3'], ['sam', '1', 'dad', '21', '-10']]

t = [[int(v) if v.lstrip('-').isnumeric() else v for v in x] for x in l]

print(t)

>>> [['aa', 2], ['bb', 3], ['sam', 1, 'dad', 21, -10]]