title: How to convert a list of strings to a list of ints in Python 3x
body: <p>I'm trying to convert a list of numbers in string format to integers.</p>
  
  <p>I've tried list comprehension: <code>marks = [int(x) for x in marks]</code> and I've also tried mapping: <code>new_list = list(map(int, marks))</code> but both of them lead to a <code>TypeError</code>:</p>
  
  <pre><code>TypeError: int() argument must be a string, a bytes-like object or a number, not 'list'
  </code></pre>
  
  <p>Full code:</p>
  
  <pre><code>size = int(input())
  students_and_marks = []
  students = []
  marks = []
  
  for x in range((size * 2)):
      students_and_marks.append(input())
  
  for x in range(1):
      students.append(students_and_marks[0::2])
      marks.append(students_and_marks[1::2])
  
  new_list = list(map(int, marks))
  </code></pre>