学习pyyaml
网上查了一圈，觉得较好的yaml教程有：
YAML 语言教程 ：http://www.ruanyifeng.com/blog/2016/07/yaml.html。
另外，在github的pyyaml库中找到一个示例：
1 #
2 # Examples from the Preview section of the YAML specification
3 # (http://yaml.org/spec/1.2/#Preview)
4 #
5
6 # Sequence of scalars 数组
7 ---
8 - Mark McGwire
9 - Sammy Sosa
10 - Ken Griffey
11
12 # Mapping scalars to scalars 字典
13 ---
14 hr: 65 # Home runs
15 avg: 0.278 # Batting average
16 rbi: 147 # Runs Batted In
17
18 # Mapping scalars to sequences 键为字符串，值为数组的字典
19 ---
20 american:
21 - Boston Red Sox
22 - Detroit Tigers
23 - New York Yankees
24 national:
25 - New York Mets
26 - Chicago Cubs
27 - Atlanta Braves
28
29 # Sequence of mappings 项为字典的数组
30 ---
31 -
32 name: Mark McGwire
33 hr: 65
34 avg: 0.278
35 -
36 name: Sammy Sosa
37 hr: 63
38 avg: 0.288
39
40 # Sequence of sequences 项为数组的数组
41 ---
42 - [name , hr, avg ]
43 - [Mark McGwire, 65, 0.278]
44 - [Sammy Sosa , 63, 0.288]
45
46 # Mapping of mappings 字典套构
47 ---
48 Mark McGwire: {hr: 65, avg: 0.278}
49 Sammy Sosa: {
50 hr: 63,
51 avg: 0.288
52 }
53
54 # Two documents in a stream
55 --- # Ranking of 1998 home runs
56 - Mark McGwire
57 - Sammy Sosa
58 - Ken Griffey
59 --- # Team ranking
60 - Chicago Cubs
61 - St Louis Cardinals
62
63 # Documents with the end indicator
64 ---
65 time: 20:03:20
66 player: Sammy Sosa
67 action: strike (miss)
68 ...
69 ---
70 time: 20:03:47
71 player: Sammy Sosa
72 action: grand slam
73 ...
74
75 # Comments
76 ---
77 hr: # 1998 hr ranking
78 - Mark McGwire
79 - Sammy Sosa
80 rbi:
81 # 1998 rbi ranking
82 - Sammy Sosa
83 - Ken Griffey
84
85 # Anchors and aliases
86 ---
87 hr:
88 - Mark McGwire
89 # Following node labeled SS
90 - &SS Sammy Sosa
91 rbi:
92 - *SS # Subsequent occurrence
93 - Ken Griffey
94
95 # Mapping between sequences
96 ---
97 ? - Detroit Tigers
98 - Chicago cubs
99 :
100 - 2001-07-23
101 ? [ New York Yankees,
102 Atlanta Braves ]
103 : [ 2001-07-02, 2001-08-12,
104 2001-08-14 ]
105
106 # Inline nested mapping
107 ---
108 # products purchased
109 - item : Super Hoop
110 quantity: 1
111 - item : Basketball
112 quantity: 4
113 - item : Big Shoes
114 quantity: 1
115
116 # Literal scalars
117 --- | # ASCII art
118 \//||\/||
119 // || ||__
120
121 # Folded scalars
122 --- >
123 Mark McGwire's
124 year was crippled
125 by a knee injury.
126
127 # Preserved indented block in a folded scalar
128 ---
129 >
130 Sammy Sosa completed another
131 fine season with great stats.
132
133 63 Home Runs
134 0.288 Batting Average
135
136 What a year!
137
138 # Indentation determines scope
139 ---
140 name: Mark McGwire
141 accomplishment: >
142 Mark set a major league
143 home run record in 1998.
144 stats: |
145 65 Home Runs
146 0.278 Batting Average
147 # Quoted scalars
148 ---
149 unicode: "Sosa did fine.\u263A"
150 control: "\b1998\t1999\t2000\n"
151 hex esc: "\x0d\x0a is \r\n"
152 single: '"Howdy!" he cried.'
153 quoted: ' # not a ''comment''.'
154 tie-fighter: '|\-*-/|'
155
156 # Multi-line flow scalars
157 ---
158 plain:
159 This unquoted scalar
160 spans many lines.
161 quoted: "So does this
162 quoted scalar.\n"
163
164 # Integers
165 ---
166 canonical: 12345
167 decimal: +12_345
168 sexagesimal: 3:25:45
169 octal: 014
170 hexadecimal: 0xC
171
172 # Floating point
173 ---
174 canonical: 1.23015e+3
175 exponential: 12.3015e+02
176 sexagesimal: 20:30.15
177 fixed: 1_230.15
178 negative infinity: -.inf
179 not a number: .NaN
180
181 # Miscellaneous
182 ---
183 null: ~
184 true: boolean
185 false: boolean
186 string: '12345'
187
188 # Timestamps
189 ---
190 canonical: 2001-12-15T02:59:43.1Z
191 iso8601: 2001-12-14t21:59:43.10-05:00
192 spaced: 2001-12-14 21:59:43.10 -5
193 date: 2002-12-14
194
195 # Various explicit tags
196 ---
197 not-date: !!str 2002-04-28
198 picture: !!binary |
199 R0lGODlhDAAMAIQAAP//9/X
200 17unp5WZmZgAAAOfn515eXv
201 Pz7Y6OjuDg4J+fn5OTk6enp
202 56enmleECcgggoBADs=
203 application specific tag: !something |
204 The semantics of the tag
205 above may be different for
206 different documents.
207 # Global tags
208 %TAG ! tag:clarkevans.com,2002:
209 --- !shape
210 # Use the ! handle for presenting
211 # tag:clarkevans.com,2002:circle
212 - !circle
213 center: &ORIGIN {x: 73, y: 129}
214 radius: 7
215 - !line
216 start: *ORIGIN
217 finish: { x: 89, y: 102 }
218 - !label
219 start: *ORIGIN
220 color: 0xFFEEBB
221 text: Pretty vector drawing.
222
223 # Unordered sets
224 --- !!set
225 # sets are represented as a
226 # mapping where each key is
227 # associated with the empty string
228 ? Mark McGwire
229 ? Sammy Sosa
230 ? Ken Griff
231
232 # Ordered mappings
233 --- !!omap
234 # ordered maps are represented as
235 # a sequence of mappings, with
236 # each mapping having one key
237 - Mark McGwire: 65
238 - Sammy Sosa: 63
239 - Ken Griffy: 58
240
241 # Full length example
242 --- !<tag:clarkevans.com,2002:invoice>
243 invoice: 34843
244 date : 2001-01-23
245 bill-to: &id001
246 given : Chris
247 family : Dumars
248 address:
249 lines: |
250 458 Walkman Dr.
251 Suite #292
252 city : Royal Oak
253 state : MI
254 postal : 48046
255 ship-to: *id001
256 product:
257 - sku : BL394D
258 quantity : 4
259 description : Basketball
260 price : 450.00
261 - sku : BL4438H
262 quantity : 1
263 description : Super Hoop
264 price : 2392.00
265 tax : 251.42
266 total: 4443.52
267 comments:
268 Late afternoon is best.
269 Backup contact is Nancy
270 Billsmer @ 338-4338.
271
272 # Another full-length example
273 ---
274 Time: 2001-11-23 15:01:42 -5
275 User: ed
276 Warning:
277 This is an error message
278 for the log file
279 ---
280 Time: 2001-11-23 15:02:31 -5
281 User: ed
282 Warning:
283 A slightly different error
284 message.
285 ---
286 Date: 2001-11-23 15:03:17 -5
287 User: ed
288 Fatal:
289 Unknown variable "bar"
290 Stack:
291 - file: TopClass.py
292 line: 23
293 code: |
294 x = MoreObject("345\n")
295 - file: MoreClass.py
296 line: 58
297 code: |-
298 foo = bar
英文不太好，很多不太会翻译。就不误导别人了，见谅。
