Python 'else' and 'if not' statement in a for loop

databasepath='/Users/software/database.txt'
sinfo=[]
soi = pnevli[1].header['OBJECT']
with open(databasepath) as fp:
   for line in fp:
       if soi in line:
           line_array = line.split(sep=None, maxsplit=-1)
           sinfo.append(line_array)
           sinfo = np.array(sinfo)[0]
           source = {
            'Name': sinfo[1],
            'PSR': sinfo[2],
            'RA': sinfo[3],
            'DEC': sinfo[5],
            'RAJD': sinfo[11],
            'DECJD': sinfo[13]
           }
           print(source)
           savepath = obspath/obsid
           file1 = open(str(savepath)+'/'+'PSR_'+soi+'.txt',"w")
           file1.write(str(source))
           file1.close()
       #if not soi in line:
           #print('The source is not listed')

I have written the above code in which it reads a header in a fits file and compares it to a database (database.txt) and if it finds a match, it copies the entire row of that database and writes it in a new text file. I have two problems here:

First problem: Lets say, the database has 1000 rows and it finds a match, if I use "if not soi in line:" or "else:", it will copy of the matched row to a text file and then prints 999 times The source is not listed because it is in a for a loop. What I actually want is to write this statement (once) only if there is no match!

Second problem: When it writes the row in the text file, I would like it to write each string in a new line (for instance 'Name': sinfo[1] first line, 'PSR': sinfo[2] second line and so on, but I don't know how exactly to insert \n so it could jumpy to a new line!