如何在较大字符串中的两个特殊字符之间找到字符串？

Question

I have a code that generates the result in a string format. The format is given by:

variable[a,b] 

where a and b are two different numbers in the string. For example, in the following there are some results:

result = "variable[21,30]"
result = "variable[19,27]"
result = "variable[11,16]"

My goal is to take the second number in the string. In the examples, the second number is 30, 27, and 16. To find them I have used the easy below code:

second number = result[12:14]

In these cases, all numbers are two digits. So I know that the second number is between the character 12 and 14 of the string. But, my problem has arisen when the digit of the numbers can be in the range of one to 4 digits. Therefore, I don't know the location of the second number in the string !. For example:

result = "variable[1,230]"
result = "variable[19,2]"
result = "variable[61,1672]"

So, how can I find the second number?

I know that the second number is between the character "," and "]". Therefore, I am thinking about a way that makes it possible for me to take a part of a string by specific symbols instead of the location. I know that the below code is not correct but just for an example, instead of defining a range, define the symbols as below:

second number = result[ "," : "]" ]

Answer 1

您可以使用以下代码：

second_number = result.split(',')[1][:-1]

Answer 2

Well, when you want to find the location of specific characters in a string you can use the find() method.

Thus when looking for the second number, your code should look like:

start = result.find(",")
end = result.find("]")
second_number = result[start+1:end]

Take care

Answer 3

You can use re.split() method:

>>> import re
>>> values = re.split(r'[\[\],]', result)
>>> values
['variable', '1', '230', '']
>>> second_number = int(values[-2])
>>> second_number
230

or

 >>> second_number = re.split(r'[\[\],]', result)[-2]
 '230'