Python - Append line under another line that contains a certain string

Question

I want to append the string "$basetexturetransform" "center .5 .5 scale 4 4 rotate 0 translate 0 0" (including the quotation marks) as a new line under every line that contains the string $basetexture.

So that, for example, the file

"LightmappedGeneric"
{
    "$basetexture" "Concrete/concrete_modular_floor001a"
    "$surfaceprop" "concrete"
    "%keywords" "portal"
}

turns into

"LightmappedGeneric"
{
    "$basetexture" "Concrete/concrete_modular_floor001a"
    "$basetexturetransform" "center .5 .5 scale 4 4 rotate 0 translate 0 0"
    "$surfaceprop" "concrete"
    "%keywords" "portal"
}

and I want to do it for every file that has the file extension ".vmt" in a folder (including sub folders).

Is there an easy way to do this in Python? I have like 400 .vmt files in a folder that I need to modify and it would be a real pain to have to do it manually.

score 2 · Accepted Answer · edited Jun 20 '20 at 09:12

This expression might likely do that with re.sub:

import re

regex = r"(\"\$basetexture\".*)"

test_str = """
"LightmappedGeneric"
{
    "$basetexture" "Concrete/concrete_modular_floor001a"
    "$surfaceprop" "concrete"
    "%keywords" "portal"
}
"LightmappedGeneric"
{
    "$nobasetexture" "Concrete/concrete_modular_floor001a"
    "$surfaceprop" "concrete"
    "%keywords" "portal"
}

"""

subst = "\\1\\n\\t\"$basetexturetransform\" \"center .5 .5 scale 4 4 rotate 0 translate 0 0\""

print(re.sub(regex, subst, test_str, 0, re.MULTILINE))

Output

"LightmappedGeneric"
{
    "$basetexture" "Concrete/concrete_modular_floor001a"
    "$basetexturetransform" "center .5 .5 scale 4 4 rotate 0 translate 0 0"
    "$surfaceprop" "concrete"
    "%keywords" "portal"
}
"LightmappedGeneric"
{
    "$nobasetexture" "Concrete/concrete_modular_floor001a"
    "$surfaceprop" "concrete"
    "%keywords" "portal"
}

If you wish to explore/simplify/modify the expression, it's been explained on the top right panel of regex101.com. If you'd like, you can also watch in this link, how it would match against some sample inputs.

Reference

Find all files in a directory with extension .txt in Python

Thanks! That will probably do the trick for a single file at least. Is there a simple way to extend this to apply it on ALL files with a ".vmt" file extention in a folder (including subfolders)? — Schytheron, Aug 24 '19 at 17:00

Python - Append line under another line that contains a certain string

1 Answers1

Output

Reference