python中的静态转换等效项 [英] Static cast equivalent in python

问题描述

我的问题如下:

我正在使用 ROS，我目前正在尝试从 Kinect 传感器的 PointCloud 读取值.值的类型为 PointCloud2，PointCloud2.data 保存 PointCloud 的数据，类型为 uint8[].

I am using ROS and I am currently trying to read values from a PointCloud of a Kinect sensor. The values are of type PointCloud2 and PointCloud2.data holds the data of the PointCloud and is of type uint8[].

在我的项目中，我目前正在使用 python 并且我已成功注册和检索数据.我的问题是，当试图检索它们时，python 将 uint8[] 数组解析为字符串.

In my project I am currently using python and I have successfully registered and retrieved the data. My issue is that when trying to retrieve them python parses the uint8[] array as strings.

我遇到问题的脚本的当前部分如下:

The current part of the script where I have the problem is the follwowing:

def PointCloud(self, PointCloud2):
    self.lock.acquire()
        for x in PointCloud2.data:
            print x
    self.lock.release()

我知道在 C++ 中我可以做类似的事情

I know that in c++ I can do something like

 std::cout << static_cast< int >( u );

获取无符号整数的值.是否有等同于 python 的静态转换?

To get the value of the unsigned integer. Is there a static cast equivalent to python?

在我的例子中，print x 输出 ASCII 字符.我如何检索它的 int 值?

In my case print x outputs ASCII characters. How could I retrieve the int value of that?

干杯，

全景

推荐答案

使用struct.unpack得到x中二进制数据编码的整数值.

Use struct.unpack to get the integer value encoded by the binary data in x.

print struct.unpack("!I", x)

(我假设 x 包含一个以网络字节顺序排列的 4 字节整数；如果您需要 以外的格式，请查阅 struct 模块的文档>!I.)

(I'm assuming x contains a 4-byte integer in network byte order; consult the documentation for the struct module if you need a format other than !I.)

更新:我错过了你有一个无符号字节数组；在这种情况下，使用

Update: I missed that you have an array of unsigned bytes; in that case, use

struct.unpack("B", x)

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