I want to extract numbers contained in an alphanumeric strings. Please help me on this.
Example:
line = ["frame_117", "frame_11","frame_1207"]
Result:
[117, 11, 1207]
3 Answers
You can split with special character '_' like this:
numbers = []
line = ["frame_117", "frame_11","frame_1207"]
for item in line:
number = int(item.split("_",1)[1])
numbers.append(number)
print(numbers)
Comments
import re
temp = []
lines = ["frame_117", "frame_11","frame_1207"]
for line in lines:
num = re.search(r'-?\d+', line)
temp.append(int(num.group(0)))
print(temp) # [117, 11, 1207]
Comments
Rationale
The first thing I see is that the names inside the list have a pattern. The string frame, an underscore _ and the string number: "frame_number".
Step-By-Step
With that in mind, you can:
- Loop through the list. We'll use a list comprehension.
- Get each item from the list (the names=
"frame_number") - Split them according to a separator (getting a sublist with [
"frame","number"]) - And then create a new list with the last items of each sublist
numbers = [x.split("_")[-1] for x in line]
['117', '11', '1207']
Solution
- But you need numbers and here you have a list of strings. We make one extra step and use
int().
numbers = [int(x.split("_")[-1]) for x in line]
[117, 11, 1207]
This works only because we detected a pattern in the target name.
But what happens if you need to find all numbers in a random string? Or floats? Or Complex numbers? Or negative numbers?
That's a little bit more complex and out of scope of this answer. See How to extract numbers from a string in Python?
[int(s.split('_')[-1]) for s in line]