我对Python相当陌生，我试图将一个文本文件中的条目由两行组成，并将其拆分为一批max。400件物品。
我正在处理的数据是数以千计的FASTA格式的序列（带标题的纯文本，用于生物信息学），其中的条目看起来像这样：

HORVU6Hr1G000325.5
PIPPPASHFHPHHQNPSAATQPLCAAMAPAAKKPPLKSSSSHNSAAGDAA
HORVU6Hr1G000326.1
MVKFTAEELRGIMDKKNNIRNMSVIAHVD
...
在Biopython中，有一个解析器SeqIO.parse，它允许将这些作为由ID和字符串组成的对象数组进行访问，我需要在代码的后面部分使用这些对象，因为我需要节省内存，所以我希望避免阅读/解析源文件的次数超过必要的次数。
在Biopython手册中，有一种推荐的方法可以通过生成器来实现这一点，我正在使用：https://biopython.org/wiki/Split_large_file
然而，我使用的是Python 3.7，而代码是Python 2.x，所以肯定有一些必要的更改。我已经改变了
entry = iterator.next（）
进入
entry = next（iterator）
但我不确定这是不是我需要改变的全部
代码如下：

def batch_iterator(iterator, batch_size=400):
    """Returns lists of length batch_size."""
    entry = True  # Make sure we loop once
    while entry:
        batch = []
        while len(batch) < batch_size:
            try:
                entry = next(iterator)
            except StopIteration:
                entry = None

            if entry is None:
                # End of file
                break
            batch.append(entry)
        if batch:
            yield batch

while True:
    bsequence = input("Please enter the full path to your FASTA file(e.g. c:\\folder1\\folder2\\protein.fasta):\n")
    try:
        fastafile = open(bsequence)
        break
    except:
        print("File not found!\n")            

record_iter = SeqIO.parse(fastafile,"fasta")
num = 0
for line in fastafile:
    if line.startswith(">"):
        num += 1

print("num=%i" % (num,))
if num > 400:
    print("The specified file contains %i sequences. It's recommended to split the FASTA file into batches of max. 400 sequences.\n" % (num,))
    while True:
        decision = input("Do you wish to create batch files? (Original file will not be overwritten)\n(Y/N):")
        if (decision == 'Y' or 'y'):
            for i, batch in enumerate(batch_iterator(record_iter, 400), 1):
                filename = "group_%i.fasta" % (i + 1)
                with open(filename, "w") as handle:
                    count = SeqIO.write(batch, handle, "fasta")
                print("Wrote %i records to %s" % (count, filename))
            break
        elif (decision == 'N' or 'n'):
            break
        else:
            print('Invalid input\n')

...next part of the code

当我运行这个程序时，在Y/N提示符之后，即使我键入Y，程序也会跳到代码的下一部分，而不会创建任何新文件。调试器显示以下内容：

Do you wish to create batch files? (Original file will not be overwritten)
(Y/N):Y
Traceback (most recent call last):
  File "\Biopython\mainscript.py", line 32, in batch_iterator
    entry = next(iterator)
StopIteration

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Program Files (x86)\Thonny\lib\site-packages\thonny\backend.py", line 1569, in _trace
    return self._trace_and_catch(frame, event, arg)

  File "C:\Program Files (x86)\Thonny\lib\site-packages\thonny\backend.py", line 1611, in _trace_and_catch
    frame.f_back, event, marker_function_args, node

  File "C:\Program Files (x86)\Thonny\lib\site-packages\thonny\backend.py", line 1656, in _handle_progress_event
    self._save_current_state(frame, event, args, node)

  File "C:\Program Files (x86)\Thonny\lib\site-packages\thonny\backend.py", line 1738, in _save_current_state
    exception_info = self._export_exception_info()

  File "C:\Program Files (x86)\Thonny\lib\site-packages\thonny\backend.py", line 1371, in _export_exception_info
    "affected_frame_ids": exc[1]._affected_frame_ids_,

AttributeError: 'StopIteration' object has no attribute '_affected_frame_ids_'

Python 2.x和Python 3.x之间有什么我忽略的区别吗？问题出在别的地方吗？这种做法是否完全错误？先谢谢你了！