# [SOLVED] Is there a math formula for converting string into integer on my own?

## Issue

EDIT: sorry if this is confusing but simply i want to make my own int() function for a school project

I am creating this code for a project at my school, the current formula I have for adding an integer to the end of a number is: "curnumber = curnumber + (integer – curnumber)", kind of like if you want x to be 13 and the current number is 2, you’d do something like "x = x + (13 – 2)" and it’d return the number but I don’t know how to combine the numbers, it’s really confusing, I’m able to get the number from a single character using this code:
`def singleint(num):`

``````    int_ = 0
if num == '0':
int_ = 0
elif num == '1':
int_ = 1
elif num == '2':
int_ = 2
elif num == '3':
int_ = 3
elif num == '4':
int_ = 4
elif num == '5':
int_ = 5
elif num == '6':
int_ = 6
elif num == '7':
int_ = 7
elif num == '8':
int_ = 8
elif num == '9':
int_ = 9
return int_`
``````

and my total current code is:

``````def singleint(num):
int_ = 0
if num == '0':
int_ = 0
elif num == '1':
int_ = 1
elif num == '2':
int_ = 2
elif num == '3':
int_ = 3
elif num == '4':
int_ = 4
elif num == '5':
int_ = 5
elif num == '6':
int_ = 6
elif num == '7':
int_ = 7
elif num == '8':
int_ = 8
elif num == '9':
int_ = 9
return int_

def tonumber(str_):
num = 0
x = 0
for char in list(str(str_)):
c = singleint(char)
print(type(c))
new = (c - num)
num = num + new
x += 1
return num

print(str(tonumber(192)))
``````

I really need help with this, thanks

## Solution

Try to see if all the characters in a string is numeric by using isnumeric() method, and if true, then use int() to convert it.

``````def convert_number(string_format):
if string_format.isnumeric():
return int(string_format)
else:
return None
``````