How to extract integers from a string

Question

Hi I am trying to extract a string from integer:
For example:

Given an input:
Input = Stal2ling

I know I can do this?
list = []

for i in Input:
try:
i = int(i)
list.append(i)
except:
print(i + "is" not an integer")

But I think this would be O(n) in time complexity.Is there a way I can make it more efficient.

My output should be a list of the integers that are in the string

Answer 1

I just found out that python has an inbuilt order for numbers and strings. Therefore
"2" is less than "e"(all numbers are less than strings even though they are in "" - string form)
Therefore it is possible to use binary search. question closed. Thankyou all for your time

Answer 2

Erlénio.RS , it's typo bro his question is how to extract integer from a string faster then O(n)

Answer 3

Best Way to Get Numbers From String:

x=input()
lst=[]
for i in x:
if i.isdigit():
lst.append(i)
else:
None
print(''.join(lst))

Answer 4

You're messing around, your problem says something, and your code illustrates something different.

If your question is how to extract integers from strings, you can use the code below:

userinput = "th6i3fh7"
for i in userinput:
if i.isdigit():
print("{0} is an integer".format(i))
else:
print (i+" is not an integer")

If that's what's at issue, extracting strings into integers, in my opinion I think it's impossible, because an integer with characters will never be accepted.

Answer 5

You could use binary search instead of linear search. Time complexity would be O(log n)

Here is an example of binary search for arrays:
https://www.google.com/amp/s/www.geeksforgeeks.org/JUMP_LINK__&&__python__&&__JUMP_LINK-program-for-binary-search/amp/

Answer 6

Richard ,yup and it's not just python,if you convert chars to int numbers will always be smaller, cuz of ASCII...