class_docstr: pad 类似于 ``[np.array([3, 4]), np.array([1])]`` 的 field 。若内部元素不为 :class:`np.ndarray` ，则必须含有 :meth:`tolist` 方法。
  
      >>> NumpyTensorPadder.pad([np.array([3, 4]), np.array([1])], pad_val=-100)
      [[   3.    4.]
       [   1. -100.]]
  :param pad_val: pad 的值是多少。
  :param ele_dtype: 用于检测当前 field 的元素类型是否可以转换为 :class:`np.array` 类型。
  :param dtype: 输出的数据的 dtype 是什么
class_docstr_tok: ["pad","\u7c7b\u4f3c\u4e8e","``","[","np.array","(","[","3",",","4","]",")",",","np.array","(","[","1","]",")","]","``","\u7684","field","\u3002\u82e5\u5185\u90e8\u5143\u7d20\u4e0d\u4e3a",":","class",":","`","np.ndarray","`","\uff0c\u5219\u5fc5\u987b\u542b\u6709",":","meth",":","`","tolist","`","\u65b9\u6cd5\u3002",">",">",">","NumpyTensorPadder.pad","(","[","np.array","(","[","3",",","4","]",")",",","np.array","(","[","1","]",")","]",",","pad_val=-100",")","[","[","3",".","4",".","]","[","1",".","-100",".","]","]",":","param","pad_val",":","pad","\u7684\u503c\u662f\u591a\u5c11\u3002",":","param","ele_dtype",":","\u7528\u4e8e\u68c0\u6d4b\u5f53\u524d","field","\u7684\u5143\u7d20\u7c7b\u578b\u662f\u5426\u53ef\u4ee5\u8f6c\u6362\u4e3a",":","class",":","`","np.array","`","\u7c7b\u578b\u3002",":","param","dtype",":","\u8f93\u51fa\u7684\u6570\u636e\u7684","dtype","\u662f\u4ec0\u4e48"]
code: def __init__(self, pad_val=0, ele_dtype=None, dtype=None):
      dtype = _get_dtype(ele_dtype, dtype, self.__class__.__name__)
      super().__init__(pad_val=pad_val, dtype=dtype)
  
file_path: fastNLP/fastNLP/core/collators/padders/numpy_padder.py
imports: from numbers import Number
  from abc import ABC
  from typing import Any, Union
  import numpy
  from .padder import Padder
  from .utils import get_padded_numpy_array, is_number_or_numpy_number
  from .exceptions import *
label_desc: Use image node_id 1 to create a new NumpyTensorPadder object from inherited base classes: Padder with example: obj = NumpyTensorPadder(pad_val, ele_dtype, dtype)