Python does not use the Int () function to convert a string to a number

Converts a string to a number without using the Int () function, such as converting the string "12345" to the number 12345. method One: Using the str function

Since we can't use the INT function, we're going to go against it and use the STR function to find out the number of digits represented by each character.

Atoi (s):
   s = s[::-1]
   num = 0
   Enumerate (s):
      Range (0)
         :  v = = str (j):
            num + + J * (* * i)
   num

method Two: Use the Ord function to find the ASCII code of each character and subtract the ASCII code of character 0 to find out the number of digits represented by the Ord.

Atoi (s):
   s = s[::-1]
   num = 0
   Enumerate (s):
      offset = ord (v)-ord (' 0 ')
      num + + offset * (i)
   num

method Three: Use the Eval functionThe Eval function evaluates the string str as a valid expression and returns the result of the calculation. We can use this feature to create an expression that multiplies 1 by each character, and then use eval to calculate the return value of the expression to denote the number of uppercase.

Atoi (s):
   s = s[::-1]
   num = 0
   Enumerate (s):
      t = '%s * 1 '% v
      n = eval (t)
      num = n * (i)
   num