| 1 | 1 | def grep(pattern: str, flags: str, files: list[str]) -> str: |
| 2 | | pass |
| 2 | """ |
| 3 | Search for lines matching a pattern in files and return matching lines. |
| 4 | |
| 5 | Args: |
| 6 | pattern: The string to search for |
| 7 | flags: String containing command line flags (-n, -l, -i, -v, -x) |
| 8 | files: List of file paths to search in |
| 9 | |
| 10 | Returns: |
| 11 | String containing all matching lines, formatted according to flags |
| 12 | """ |
| 13 | # Parse flags |
| 14 | line_numbers = '-n' in flags |
| 15 | files_only = '-l' in flags |
| 16 | case_insensitive = '-i' in flags |
| 17 | invert_match = '-v' in flags |
| 18 | exact_match = '-x' in flags |
| 19 | |
| 20 | results = [] |
| 21 | |
| 22 | # Edge Case: No files provided |
| 23 | if not files: |
| 24 | return "" |
| 25 | |
| 26 | multiple_files = len(files) > 1 |
| 27 | |
| 28 | for file_path in files: |
| 29 | # Edge Case: File not found |
| 30 | try: |
| 31 | with open(file_path, 'r', encoding='utf-8') as file: |
| 32 | lines = file.readlines() |
| 33 | except FileNotFoundError: |
| 34 | # According to typical grep behavior, we silently skip missing files |
| 35 | continue |
| 36 | |
| 37 | # Edge Case: File with no lines |
| 38 | if not lines: |
| 39 | continue |
| 40 | |
| 41 | file_has_match = False |
| 42 | |
| 43 | for line_num, line in enumerate(lines, 1): |
| 44 | # Remove newline for processing but keep it for output |
| 45 | line_content = line.rstrip('\n') |
| 46 | |
| 47 | # Determine if line matches |
| 48 | if case_insensitive: |
| 49 | match = pattern.lower() in line_content.lower() |
| 50 | exact = pattern.lower() == line_content.lower() |
| 51 | else: |
| 52 | match = pattern in line_content |
| 53 | exact = pattern == line_content |
| 54 | |
| 55 | # Apply exact match flag |
| 56 | if exact_match: |
| 57 | match = exact |
| 58 | |
| 59 | # Apply invert flag |
| 60 | if invert_match: |
| 61 | match = not match |
| 62 | |
| 63 | if match: |
| 64 | file_has_match = True |
| 65 | |
| 66 | # If we only need file names, we can break early |
| 67 | if files_only: |
| 68 | break |
| 69 | |
| 70 | # Build output line |
| 71 | output_line = "" |
| 72 | |
| 73 | # Add file name if multiple files |
| 74 | if multiple_files: |
| 75 | output_line += f"{file_path}:" |
| 76 | |
| 77 | # Add line number if requested |
| 78 | if line_numbers: |
| 79 | output_line += f"{line_num}:" |
| 80 | |
| 81 | # Add content |
| 82 | output_line += line |
| 83 | |
| 84 | results.append(output_line) |
| 85 | |
| 86 | # If we only need file names and this file had a match |
| 87 | if files_only and file_has_match: |
| 88 | results.append(file_path + "\n") |
| 89 | |
| 90 | # Edge Case: No matches found |
| 91 | # This is handled naturally by returning an empty string |
| 92 | |
| 93 | # Join all results |
| 94 | return ''.join(results) |
| 95 | |
| 96 | # Handled Edge Cases: No files provided, File not found, File with no lines, No matches found |