python 按行数分割文件

def split_file_by_line(file_name, split_lines):
    split_files = []
    file_idx = 1
    line_ct = 0
    with open(file_name, 'r', encoding='utf-8') as fin:
        for line in fin:
            if line_ct == 0:
                part_file = file_name + '_part_' + str(file_idx)
                fout = open(part_file, 'w', encoding='utf-8')
                split_files.append(part_file)
            fout.write(line)
            line_ct += 1
            if line_ct >= split_lines:
                line_ct = 0
                fout.close()
                file_idx += 1
    print(f'file: {file_name}, split lines: {split_lines}, split files num: {len(split_files)}')
    return split_files

$ cat test
1
2
3
4

$ 

>>> split_file_by_line('test', 2)
['test_part_1', 'test_part_2', 'test_part_3']
>>> split_file_by_line('test', 3)
['test_part_1', 'test_part_2']
>>> split_file_by_line('test', 1)
['test_part_1', 'test_part_2', 'test_part_3', 'test_part_4', 'test_part_5']
>>> split_file_by_line('test', 4)
['test_part_1', 'test_part_2']
>>> split_file_by_line('test', 5)
['test_part_1']
>>> split_file_by_line('test', 6)
['test_part_1']
>>> split_file_by_line('test', 7)
['test_part_1']