在python中将字符串中的子字符串替换为null

Question

I have a string as

a='''123
456
789'''

I want to replace 456 with something similar to a null value, so that the corresponding output is

123
789

The objective is to eliminate the empty line that would be generated as a result of

a=a.replace('456','')

Answer 1

You are getting empty line after doing replace because '456' is followed by '\\n' . In order to remove empty line, replace '456\\n' with '' as:

>>> a = a.replace('456\n', '')
>>> print(a)
123
789

where initially a is holding the multiline string mentioned in the question as:

>>> a='''123
    456
    789'''