高效地从一个文件中查找另一个文件中的行

def find_lines_in_file(file1_path, file2_path):
    # 读取第一个文件并存储在哈希表中
    lines_set = set()
    with open(file1_path, 'r') as file1:
        for line in file1:
            lines_set.add(line.strip())
    
    # 查找第二个文件中的行
    found_lines = []
    with open(file2_path, 'r') as file2:
        for line in file2:
            if line.strip() in lines_set:
                found_lines.append(line.strip())
    
    return found_lines

# 示例调用
result = find_lines_in_file('file1.txt', 'file2.txt')
print(result)

import heapq

def external_sort(file_path):
    temp_files = []
    with open(file_path, 'r') as file:
        while True:
            lines = file.readlines(1024 * 1024)  # 每次读取1MB数据
            if not lines:
                break
            lines.sort()
            temp_file = f'temp_{len(temp_files)}.txt'
            with open(temp_file, 'w') as temp:
                temp.writelines(lines)
            temp_files.append(temp_file)
    return temp_files

def merge_files(files):
    merged_file = 'merged.txt'
    with open(merged_file, 'w') as outfile:
        heap = []
        for file in files:
            f = open(file, 'r')
            first_line = f.readline()
            if first_line:
                heapq.heappush(heap, (first_line, f))
        
        while heap:
            smallest, f = heapq.heappop(heap)
            outfile.write(smallest)
            next_line = f.readline()
            if next_line:
                heapq.heappush(heap, (next_line, f))
            else:
                f.close()
                os.remove(f.name)
    
    for file in files:
        os.remove(file)
    return merged_file

def find_lines_in_file(file1_path, file2_path):
    sorted_files1 = external_sort(file1_path)
    sorted_files2 = external_sort(file2_path)
    
    merged_file1 = merge_files(sorted_files1)
    merged_file2 = merge_files(sorted_files2)
    
    found_lines = []
    with open(merged_file1, 'r') as file1, open(merged_file2, 'r') as file2:
        line1 = file1.readline()
        line2 = file2.readline()
        while line1 and line2:
            if line1 == line2:
                found_lines.append(line1.strip())
                line1 = file1.readline()
                line2 = file2.readline()
            elif line1 < line2:
                line1 = file1.readline()
            else:
                line2 = file2.readline()
    
    os.remove(merged_file1)
    os.remove(merged_file2)
    
    return found_lines

# 示例调用
result = find_lines_in_file('file1.txt', 'file2.txt')
print(result)