错误：

---------------------------------------------------------------------------InvalidArgumentError Traceback (most recent call last)C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\tensorflow\python\client\session.py in _do_call(self, fn, *args) 1326 try:-> 1327 return fn(*args) 1328 except errors.OpError as e:C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\tensorflow\python\client\session.py in _run_fn(session, feed_dict, fetch_list, target_list, options, run_metadata) 1305 feed_dict, fetch_list, target_list,-> 1306 status, run_metadata) 1307 C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\contextlib.py in __exit__(self, type, value, traceback) 65 try:---> 66 next(self.gen) 67 except StopIteration:C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\tensorflow\python\framework\errors_impl.py in raise_exception_on_not_ok_status() 465 compat.as_text(pywrap_tensorflow.TF_Message(status)),--> 466 pywrap_tensorflow.TF_GetCode(status)) 467 finally:InvalidArgumentError: You must feed a value for placeholder tensor 'Placeholder_2' with dtype float and shape [?,10]

[[Node: Placeholder_2 = Placeholder[dtype=DT_FLOAT, shape=[?,10], _device="/job:localhost/replica:0/task:0/cpu:0"]()]]

During handling of the above exception, another exception occurred:InvalidArgumentError                      Traceback (most recent call last) in ()      2 for i in range(1000):      3    batch_xs,batch_ys = mnist.train.next_batch(100)----> 4    sess.run(train_step,feed_dict={x:batch_xs,y:batch_ys})C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\tensorflow\python\client\session.py in run(self, fetches, feed_dict, options, run_metadata)    893    try:    894      result = self._run(None, fetches, feed_dict, options_ptr,--> 895                          run_metadata_ptr)    896      if run_metadata:    897        proto_data = tf_session.TF_GetBuffer(run_metadata_ptr)C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\tensorflow\python\client\session.py in _run(self, handle, fetches, feed_dict, options, run_metadata)  1122    if final_fetches or final_targets or (handle and feed_dict_tensor):  1123      results = self._do_run(handle, final_targets, final_fetches,-> 1124                              feed_dict_tensor, options, run_metadata)  1125    else:  1126      results = []C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\tensorflow\python\client\session.py in _do_run(self, handle, target_list, fetch_list, feed_dict, options, run_metadata)  1319    if handle is None:  1320      return self._do_call(_run_fn, self._session, feeds, fetches, targets,-> 1321                            options, run_metadata)  1322    else:  1323      return self._do_call(_prun_fn, self._session, handle, feeds, fetches)C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\tensorflow\python\client\session.py in _do_call(self, fn, *args)  1338        except KeyError:  1339          pass-> 1340      raise type(e)(node_def, op, message)  1341    1342  def _extend_graph(self):InvalidArgumentError: You must feed a value for placeholder tensor 'Placeholder_2' with dtype float and shape [?,10]

[[Node: Placeholder_2 = Placeholder[dtype=DT_FLOAT, shape=[?,10], _device="/job:localhost/replica:0/task:0/cpu:0"]()]]

Caused by op 'Placeholder_2', defined at:

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\runpy.py", line 193, in _run_module_as_main

    "__main__", mod_spec)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\runpy.py", line 85, in _run_code

    exec(code, run_globals)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\ipykernel_launcher.py", line 16, in

    app.launch_new_instance()

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\traitlets\config\application.py", line 658, in launch_instance

    app.start()

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\ipykernel\kernelapp.py", line 477, in start

    ioloop.IOLoop.instance().start()

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\zmq\eventloop\ioloop.py", line 177, in start

    super(ZMQIOLoop, self).start()

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\tornado\ioloop.py", line 888, in start

    handler_func(fd_obj, events)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\tornado\stack_context.py", line 277, in null_wrapper

    return fn(*args, **kwargs)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\zmq\eventloop\zmqstream.py", line 440, in _handle_events

    self._handle_recv()

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\zmq\eventloop\zmqstream.py", line 472, in _handle_recv

    self._run_callback(callback, msg)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\zmq\eventloop\zmqstream.py", line 414, in _run_callback

    callback(*args, **kwargs)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\tornado\stack_context.py", line 277, in null_wrapper

    return fn(*args, **kwargs)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\ipykernel\kernelbase.py", line 283, in dispatcher

    return self.dispatch_shell(stream, msg)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\ipykernel\kernelbase.py", line 235, in dispatch_shell

    handler(stream, idents, msg)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\ipykernel\kernelbase.py", line 399, in execute_request

    user_expressions, allow_stdin)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\ipykernel\ipkernel.py", line 196, in do_execute

    res = shell.run_cell(code, store_history=store_history, silent=silent)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\ipykernel\zmqshell.py", line 533, in run_cell

    return super(ZMQInteractiveShell, self).run_cell(*args, **kwargs)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\IPython\core\interactiveshell.py", line 2717, in run_cell

    interactivity=interactivity, compiler=compiler, result=result)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\IPython\core\interactiveshell.py", line 2821, in run_ast_nodes

    if self.run_code(code, result):

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\IPython\core\interactiveshell.py", line 2881, in run_code

    exec(code_obj, self.user_global_ns, self.user_ns)

  File "", line 1, in

    y_ = tf.placeholder("float",[None,10])

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\tensorflow\python\ops\array_ops.py", line 1548, in placeholder

    return gen_array_ops._placeholder(dtype=dtype, shape=shape, name=name)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\tensorflow\python\ops\gen_array_ops.py", line 2077, in _placeholder

    name=name)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\tensorflow\python\framework\op_def_library.py", line 767, in apply_op

    op_def=op_def)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\tensorflow\python\framework\ops.py", line 2628, in create_op

    original_op=self._default_original_op, op_def=op_def)

  File "C:\Users\yyuqi\Anaconda3\envs\tensorflow\lib\site-packages\tensorflow\python\framework\ops.py", line 1204, in __init__

    self._traceback = self._graph._extract_stack()  # pylint: disable=protected-access

InvalidArgumentError (see above for traceback): You must feed a value for placeholder tensor 'Placeholder_2' with dtype float and shape [?,10]

[[Node: Placeholder_2 = Placeholder[dtype=DT_FLOAT, shape=[?,10], _device="/job:localhost/replica:0/task:0/cpu:0"]()]]

解决：

y应该改为y_