Question

new in Python (and almost in programming).

I have a file with some lines, for example

...
dr=%%dr
mkl=%%mkl
...

I want to replace the %%dr and %%mkl with zeroes in order to have, for example

...
dr=0
mkl=0
...

BUT I don’t know in advance which names I will have (whether dr, mkl or some other strange name), so I’d like to write a code that finds any “%%” and replace it and the rest of the line with a 0.

Answer 1

I believe you are looking for something similar to this using regex.

Note in the regex "%%.*$", matches everything from %% to end of line. Per your requirement, as shown in this example, multiple instances of the your pattern won’t be considered as the first pattern would be replaced till the eol.

>>> st="""new in Python (and almost in programming).

I have a file with some lines, for example

...

dr=%%dr

mkl=%%mkl

...

I want to replace the %%dr and %%mkl with zeroes in order to have, for example

..."""
>>> lines = (re.sub("%%.*$","0",line) for line in st.splitlines())
>>> print '\n'.join(lines)
new in Python (and almost in programming).

I have a file with some lines, for example

...

dr=0

mkl=0

...

I want to replace the 0

...
>>>