find_files_not_matching.py

#Search for files that do NOT contain a given string
#Import os module
import os

# Ask the user to enter string to search
search_path = input("Enter directory path to search : ")
file_type = input("File Type : ")
search_str = input("Enter the search string : ")

# Append a directory separator if not already present
#if not (search_path.endswith("/") or search_path.endswith("\\") ): 
#        search_path = search_path + "/"
                                                          
# If path does not exist, set search path to current directory
if not os.path.exists(search_path):
        search_path ="."

results = []

# Repeat for each file in the directory  
#for fname in os.listdir(path=search_path):
for fname in [os.path.join(dp, f) for dp, dn, fn in os.walk(os.path.expanduser(search_path)) for f in fn]:

   # Apply file type filter   
   if fname.endswith(file_type):

        # Open file for reading
        fo = open(fname)
        #Add the file to the results array
        results.append(fname)

        # Read the first line from the file
        line = fo.readline()

        # Initialize counter for line number
        line_no = 1

        # Loop until EOF
        while line != '' :
                # Search for string in line
                index = line.find(search_str)

                if ( index != -1) :
                    #If a line does contain the file, remove the file from results array and move on to next file
                    results.remove(fname)
                    break

                # Read next line
                line = fo.readline()  

                # Increment line counter
                line_no += 1
        # Close the files
        fo.close()
print('Search string \"' + search_str + '\" not found in following files:')        
print(*results,sep='\n')