# array_length¶

paddle.fluid.layers. array_length ( array ) [源代码]

## 参数¶

• array (LoDTensorArray) - 输入的数组LoDTensorArray

## 返回¶

shape为[1]的1-D Tensor，表示数组LoDTensorArray的长度，数据类型为int64

Variable

## 代码示例¶

```import paddle.fluid as fluid
tmp = fluid.layers.zeros(shape=[10], dtype='int32')
i = fluid.layers.fill_constant(shape=[1], dtype='int64', value=10)
#tmp是shape为[10]的Tensor，将tmp写入到数组arr下标为10的位置，arr的长度因此为11
arr = fluid.layers.array_write(tmp, i=i)
#查看arr的长度
arr_len = fluid.layers.array_length(arr)

#可以通过executor打印出LoDTensorArray的长度
input = fluid.layers.Print(arr_len, message="The length of LoDTensorArray:")
main_program = fluid.default_main_program()
exe = fluid.Executor(fluid.CPUPlace())
exe.run(main_program)
```

```import paddle.fluid as fluid
tmp = fluid.layers.zeros(shape=[10], dtype='int32')
i = fluid.layers.fill_constant(shape=[1], dtype='int64', value=10)
# tmp is 1-D Tensor with shape [10]. We write tmp into arr on subscript 10,
# then the length of arr becomes 11.
arr = fluid.layers.array_write(tmp, i=i)
# return the length of arr
arr_len = fluid.layers.array_length(arr)

# You can use executor to print out the length of LoDTensorArray.
input = fluid.layers.Print(arr_len, message="The length of LoDTensorArray:")
main_program = fluid.default_main_program()
exe = fluid.Executor(fluid.CPUPlace())
exe.run(main_program)

# The printed result is:

# 1569576542  The length of LoDTensorArray:   The place is:CPUPlace
# Tensor[array_length_0.tmp_0]
#    shape: [1,]
#    dtype: l
#    data: 11,

# 1-D Tensor with shape [1], whose value is 11. It means that the length of LoDTensorArray
# is 11.
# dtype is the corresponding C++ data type, which may vary in different environments.
# Eg: if the data type of tensor is int64, then the corresponding C++ data type is int64_t,
#       so the dtype value is typeid(int64_t).Name(), which is 'x' on MacOS, 'l' on Linux,
#       and '__int64' on Windows. They both represent 64-bit integer variables.
```