lcm實例(Python API)

文件夾結構

.
├── example_t.lcm
├── exlcm
│   ├── example_t.py
│   ├── __init__.py
│   └── __pycache__
│       ├── example_t.cpython-36.pyc
│       └── __init__.cpython-36.pyc
├── test_publish.py
└── test_subscribe.py

2 directories, 7 files

1. 文件example_t.lcm

內容：

package exlcm;

struct example_t
{
    int64_t  timestamp;
    double   position[3];
    double   orientation[4];
    int32_t  num_ranges;
    int16_t  ranges[num_ranges];
    string   name;
    boolean  enabled;
}

在命令行中執行以下命令生成lcm格式python文件：

# 此處-p是指python
lcm-gen -p example_t.lcm

生成的文件在exlcm/example_t.py

2. 文件test_publish.py

import lcm
from exlcm import example_t

msg = example_t()
msg.timestamp = 0
msg.position = (1, 2, 3)
msg.orientation = (1, 0, 0, 0)
msg.ranges = range(15)
msg.num_ranges = len(msg.ranges)
msg.name = "example string"
msg.enabled = True

lc = lcm.LCM()
while True:
    lc.publish("EXAMPLE", msg.encode())

3. 文件 test_subscribe.py

import lcm
from exlcm import example_t

def my_handler(channel, data):
    msg = example_t.decode(data)
    print("Received message on channel \"%s\"" % channel)
    print("   timestamp   = %s" % str(msg.timestamp))
    print("   position    = %s" % str(msg.position))
    print("   orientation = %s" % str(msg.orientation))
    print("   ranges: %s" % str(msg.ranges))
    print("   name        = '%s'" % msg.name)
    print("   enabled     = %s" % str(msg.enabled))
    print("")

lc = lcm.LCM()
subscription = lc.subscribe("EXAMPLE", my_handler)

try:
    while True:
        lc.handle()
except KeyboardInterrupt:
    pass

測試

在命令行中測試：python test_publish.py新開一個命令行窗口輸入python test_subscribe.py,輸出結果如下：

Received message on channel "EXAMPLE"
   timestamp   = 0
   position    = (1.0, 2.0, 3.0)
   orientation = (1.0, 0.0, 0.0, 0.0)
   ranges: (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
   name        = 'example string'
   enabled     = True

lcm教程與實例(C++ API)