How to extract a part of the string in python?

user_16034553 0
Viewed 63

I have the following list:

lst = ['SDO_GEOMETRY(2001, NULL, MDSYS.SDO_POINT_TYPE(9971, 18847, NULL), NULL, NULL)', 
'SDO_GEOMETRY(2001, NULL, MDSYS.SDO_POINT_TYPE(9971, 19188, NULL), NULL, NULL)',
'SDO_GEOMETRY(2001, NULL, MDSYS.SDO_POINT_TYPE(9972, 18282, NULL), NULL, NULL)',
'SDO_GEOMETRY(2001, NULL, MDSYS.SDO_POINT_TYPE(9977, 19201, NULL), NULL, NULL)',
'SDO_GEOMETRY(2001, NULL, MDSYS.SDO_POINT_TYPE(9989, 18635, NULL), NULL, NULL)']

I would like to extract only the string that contains the number in brackets after MDSYS.SDO_POINT_TYPE. How do I do that?

What I tried so far?

op=[]
for i in lst:
    x = (i[46:56])
    y = str('('+x+')')
    op.append(y)

But, the numbers are not always in position 46-56, how do I optimize that?

Desired output:

['(9971, 1884)',
 '(9971, 1918)',
 '(9972, 1828)',
 '(9977, 1920)',
 '(9989, 1863)']
extract substring list python string
3 Answers

You can use regular expressions:

import re
>>> [re.findall("MDSYS.SDO_POINT_TYPE\((\d+, \d+)", s)[0] for s in lst]
['9971, 18847', '9971, 19188', '9972, 18282', '9977, 19201', '9989, 18635']
user_98576310

I am using simply split to break it in list and combining again with string

lst = ['SDO_GEOMETRY(2001, NULL, MDSYS.SDO_POINT_TYPE(9971, 18847, NULL), NULL, NULL)', 
    'SDO_GEOMETRY(2001, NULL, MDSYS.SDO_POINT_TYPE(9971, 19188, NULL), NULL, NULL)',
    'SDO_GEOMETRY(2001, NULL, MDSYS.SDO_POINT_TYPE(9972, 18282, NULL), NULL, NULL)',
    'SDO_GEOMETRY(2001, NULL, MDSYS.SDO_POINT_TYPE(9977, 19201, NULL), NULL, NULL)',
    'SDO_GEOMETRY(2001, NULL, MDSYS.SDO_POINT_TYPE(9989, 18635, NULL), NULL, NULL)']

new_lst = []
for st in lst:
  name,points = st.split('MDSYS.SDO_POINT_TYPE(')
  f_num, s_num, *rest_ = points.split(',')
  new_lst.append(f"({f_num},{s_num})")

print(new_lst)
user_52604000

If the numbers between the parenthesis and the NULL can be at different positions, you can use a pattern to first get the values between parenthesis in a capture group.

Then you can find the digits in the group 1 value.

\bMDSYS\.SDO_POINT_TYPE\(([^()]+)\)
  • \bMDSYS\.SDO_POINT_TYPE\( match MDSYS\.SDO_POINT_TYPE(
  • ([^()]+) Capture all between parenthesis in group 1
  • \) Match closing )

See a Python demo ad a Regex demo

Note that in desired output the last digit is missing for the second value.

import re

lst = ['SDO_GEOMETRY(2001, NULL, MDSYS.SDO_POINT_TYPE(9971, 18847, NULL), NULL, NULL)',
       'SDO_GEOMETRY(2001, NULL, MDSYS.SDO_POINT_TYPE(9971, 19188, NULL), NULL, NULL)',
       'SDO_GEOMETRY(2001, NULL, MDSYS.SDO_POINT_TYPE(9972, 18282, NULL), NULL, NULL)',
       'SDO_GEOMETRY(2001, NULL, MDSYS.SDO_POINT_TYPE(9977, 19201, NULL), NULL, NULL)',
       'SDO_GEOMETRY(2001, NULL, MDSYS.SDO_POINT_TYPE(9989, 18635, NULL), NULL, NULL)']

op = []
for s in lst:
    m = re.search(r"\bMDSYS\.SDO_POINT_TYPE\(([^()]+)\)", s)
    if m:
        op.append("({})".format(", ".join(re.findall(r"\d+", m.group(1)))))

print(op)

Output

['(9971, 18847)', '(9971, 19188)', '(9972, 18282)', '(9977, 19201)', '(9989, 18635)']
user_54249880
Related