Python - glob.glob with grep?

Question

I am fairly new to the Python environment and gradually working my way forward.

We got about 10,000 files in a folder containing similar information, but with one major difference. Some files contain a string 'string1' and the other set contains 'string2'. Just to clarify the string is not in the filename but in the file itself. The file content is character-delimited.

I tried to create two separate lists with string1 respectively string2 and got various lines of code but getting nowhere. Both list should only contain the filename.

Answer 1

I often use grep for those kind of things. In this case I would use

Edited to add file extensions:

grep -l string1 *.txt > string1_files.txt && grep -l string2 *.txt> string2_files.txt 

This oneliner would search string1 in txt files in the current dir, writing output to string1_files.txt and similarly for string2

copying from man grep

 -l, --files-with-matches
         Only the names of files containing selected lines are written to
         standard output.  grep will only search a file until a match has
         been found, making searches potentially less expensive.  Path-
         names are listed once per file searched.  If the standard input
         is searched, the string ``(standard input)'' is written.

Hope this helps a bit but you might want to grep only certain file extensions

Edit for no file extensions: (in case they are not available as in the question comments

grep -l string1 * > string1_files.txt && grep -l string2 *> string2_files.txt 

Answer 2

Assuming your file just have the string that you want to compare, you just need to do

folder = 'foo'
files = glob.glob(os.path.join(folder, "*"))

list1 = []
list2 = []
for file in files:
  with open(file, 'r') as f:
    if(f.readlines().strip() == 'string1'):
      list1.append(file)
    else
      list2.append(file)

If your files have more data, you just need to process f.readlines() and compare properly.