阅读YAML在python

Question

我有一个YAML文件看起来像

--- 
level_1: "test" 
level_2: 'NetApp, SOFS, ZFS Creation' 
request: 341570 
--- 
level_1: "test" 
level_2: 'NetApp, SOFS, ZFS Creation' 
request: 341569 
--- 
level_1: "test" 
level_2: 'NetApp, SOFS, ZFS Creation' 
request: 341568 

我能够在Perl使用YAML正确地读这一点，但使用YAML不是在蟒蛇。它失败，出现错误：

expected a single document in the stream

计划：

import yaml 

stram = open("test", "r") 
print yaml.load(stram) 

错误：

Traceback (most recent call last): 
    File "abcd", line 4, in <module> 
    print yaml.load(stram) 
    File "/usr/local/pkgs/python-2.6.5/lib/python2.6/site-packages/yaml/__init__.py", line 58, in load 
    return loader.get_single_data() 
    File "/usr/local/pkgs/python-2.6.5/lib/python2.6/site-packages/yaml/constructor.py", line 42, in get_single_data 
    node = self.get_single_node() 
    File "/usr/local/pkgs/python-2.6.5/lib/python2.6/site-packages/yaml/composer.py", line 43, in get_single_node 
    event.start_mark) 
yaml.composer.ComposerError: expected a single document in the stream 
    in "test", line 2, column 1 
but found another document 
    in "test", line 5, column 1 

Answer 1

YAML的文件由---分离，如果任何流（例如文件）中含有较多那么您应该使用yaml.load_all函数而不是yaml.load。的代码：

import yaml 

stream = open("test", "r") 
docs = yaml.load_all(stream) 
for doc in docs: 
    for k,v in doc.items(): 
     print k, "->", v 
    print "\n", 

导致用于如在问题中提供的输入的文件：

request -> 341570 
level_1 -> test 
level_2 -> NetApp, SOFS, ZFS Creation 

request -> 341569 
level_1 -> test 
level_2 -> NetApp, SOFS, ZFS Creation 

request -> 341568 
level_1 -> test 
level_2 -> NetApp, SOFS, ZFS Creation