import re
def processArray(array):
newArray = []
for l in array:
m = re.findall(r"\[(.*?)]", " ".join(l))
for n in m:
k = re.findall(r'[A-Za-z0-9+-]+', n)
if k:
newArray.extend(k)
return newArray
print(processArray([['Preconditions [+Here]\n'], ['Preconditions [+Is', '+The]\n'], ['Preconditions [-Example]\n']]))
aW1wb3J0IHJlCgpkZWYgcHJvY2Vzc0FycmF5KGFycmF5KToKICAgIG5ld0FycmF5ID0gW10KICAgIGZvciBsIGluIGFycmF5OgogICAgICAgIG0gPSByZS5maW5kYWxsKHIiXFsoLio/KV0iLCAiICIuam9pbihsKSkKICAgICAgICBmb3IgbiBpbiBtOgogICAgICAgIAlrID0gcmUuZmluZGFsbChyJ1tBLVphLXowLTkrLV0rJywgbikKICAgICAgICAJaWYgazoKICAgICAgICAJICAgIG5ld0FycmF5LmV4dGVuZChrKQogICAgcmV0dXJuIG5ld0FycmF5CgpwcmludChwcm9jZXNzQXJyYXkoW1snUHJlY29uZGl0aW9ucyBbK0hlcmVdXG4nXSwgWydQcmVjb25kaXRpb25zIFsrSXMnLCAnK1RoZV1cbiddLCBbJ1ByZWNvbmRpdGlvbnMgWy1FeGFtcGxlXVxuJ11dKSk=