python：将for循环转换为递归函数
问题内容：
首先，我仍然是python的新手，所以请放轻松。
我已经完成了研究，并且对如何编写递归函数有基本的了解，但是我对前面的任务完全感到困惑。
我真的想要一些提示和指示，以便我自己做才能真正理解。
这是任务：
- 遍历字典
- 检查是否有“儿童”钥匙
- 如果为真，请采取措施
- 重复
这是问题
“ option”键嵌套在另一个称为“ children”的键中。在那里，我想遍历每个“儿童”键，直到它们不再存在为止。
这是没有递归的代码。当然，它会失败，因为它过于简单，过于僵化。
#level(one/two/three) refer to the level of nesting, easier for me to know where I am in the loop.
#qdf_v2 is a particular type of file which is essentially a dictionary
for levelone in qdf_v2['children']:
if 'children' in levelone:
store = options
for leveltwo in levelone['children']:
if 'children' in leveltwo:
store = options
for levelthree in leveltwo['children']:
if 'children' in levellevel:
repeat....
我想遍历字典，这是“儿童”键，直到它们不再存在为止。
您可以在这里复制一些JSON，并将其粘贴到http://www.jsoneditoronline.org/中，以查看正在使用的JSON
。
{
"base": "http://panoptic-fearless.ldc.yougov.net/questionnaires/Test_maj_demo_newG4_2/versions/12/",
"children": [
{
"name": "one",
"children": [
{
"name": "measures",
"children": [
{
"type": "single",
"options": {
"sort_order": "asending",
"chart_layout": "5",
"chart_type": "bar",
"chart_color": "green"
},
"text": "How much would you say you like or dislike P.E. at school? ",
"name": "KYS_Q1",
"responses": {
"items": [
{
"code": 1,
"text": "I love it",
"element": "qdf:response"
},
{
"code": 2,
"text": "I like it",
"element": "qdf:response"
},
{
"code": 3,
"text": "I don’t like it",
"element": "qdf:response"
},
{
"code": 4,
"text": "I hate it",
"element": "qdf:response"
},
{
"code": 5,
"text": "Don’t know",
"element": "qdf:response"
}
],
"element": "qdf:response_group"
},
"element": "qdf:question",
"export": [
{
"name": "KYS_Q1"
}
]
},
{
"children": [
{
"type": "single",
"options": {
"sort_order": "asending",
"chart_layout": "4",
"chart_type": "pie",
"chart_color": "pink"
},
"text": "{multiple order=\"randomize\" max=3} You said that you $event P.E. at school...<br/> Which THREE of the following are your MAIN reasons for not liking P.E. at school? (Please tick up to three options)",
"name": "KYS_Q2",
"responses": {
"items": [
{
"code": 1,
"text": "I don't like going outside in bad weather (e.g. in the cold, rain etc.)",
"element": "qdf:response"
},
{
"code": 2,
"text": "I’m always picked last to join a team",
"element": "qdf:response"
},
{
"code": 3,
"text": "I don't like my P.E. teacher/ don’t think they are very good",
"element": "qdf:response"
},
{
"code": 4,
"text": "I’m not very good at it",
"element": "qdf:response"
},
{
"code": 5,
"text": "I find the games/ sports we play boring",
"element": "qdf:response"
}
],
"element": "qdf:response_group"
},
"element": "qdf:question",
"export": [
{
"name": "KYS_Q2"
}
]
},
{
"type": "single",
"options": {
"sort_order": "asending",
"chart_layout": "5",
"chart_type": "line",
"chart_color": "green"
},
"text": "{multiple order=\"randomize\"} Below are some feelings that people can have about doing P.E. at school...<br/> Which of the following words describe how you feel about doing P.E. at school? (Please tick all that apply) ",
"name": "KYS_Q3A",
"responses": {
"items": [
{
"code": 1,
"text": "Stressed",
"element": "qdf:response"
},
{
"code": 2,
"text": "Scared",
"element": "qdf:response"
},
{
"code": 3,
"text": "Worried",
"element": "qdf:response"
},
{
"code": 4,
"text": "Sick",
"element": "qdf:response"
},
{
"code": 5,
"text": "Tiring ",
"element": "qdf:response"
}
],
"element": "qdf:response_group"
},
"element": "qdf:question",
"export": [
{
"name": "KYS_Q3A"
}
]
}
],
"element": "qdf:section"
},
{
"type": "single",
"options": {
"sort_order": "desending",
"chart_layout": "5",
"chart_type": "bar",
"chart_color": "green"
},
"text": "{single order=\"randomize\"} You said that you $event P.E...<br/> Which ONE of the following is the main reason you like it? ",
"name": "KYS_Q4",
"responses": {
"items": [
{
"code": 1,
"text": "I like getting outside/ not being in the classroom",
"element": "qdf:response"
},
{
"code": 2,
"text": "I like my P.E. teacher",
"element": "qdf:response"
},
{
"code": 3,
"text": "I’m good at it",
"element": "qdf:response"
},
{
"code": 4,
"text": "I find the games/ sports fun",
"element": "qdf:response"
},
{
"code": 5,
"text": "I find the games/ sports easy",
"element": "qdf:response"
}
],
"element": "qdf:response_group"
},
"element": "qdf:question",
"export": [
{
"name": "KYS_Q4"
}
]
}
],
"element": "qdf:page"
}
],
"element": "qdf:module"
},
{
"name": "two",
"children": [
{
"name": "test",
"children": [
{
"type": "single",
"options": {
"sort_order": "asending",
"chart_layout": "5",
"chart_type": "bar",
"chart_color": "green"
},
"text": "{multiple order=\"randomize\"}Below are some feelings that people can have about doing P.E at school...<br/> Which of the following words describe how you feel about doing P.E. at school? (Please tick all that apply) ",
"name": "KYS_Q5A",
"responses": {
"items": [
{
"code": 1,
"text": "Energised/ Awake",
"element": "qdf:response"
},
{
"code": 2,
"text": "Excited",
"element": "qdf:response"
},
{
"code": 3,
"text": "Relaxed",
"element": "qdf:response"
},
{
"code": 4,
"text": "Confident",
"element": "qdf:response"
},
{
"code": 5,
"text": "Happy",
"element": "qdf:response"
}
],
"element": "qdf:response_group"
},
"element": "qdf:question",
"export": [
{
"name": "KYS_Q5A"
}
]
},
{
"type": "single",
"options": {
"sort_order": "asending",
"chart_layout": "25",
"chart_type": "column",
"chart_color": "orange"
},
"text": "{multiple order=\"randomize\"} For the following question please do not be afraid to be as honest as possible, no one else will be told your personal answers. <br/> Which of the following have you EVER done in order to avoid taking part in P.E. at school? (Please tick all that apply) ",
"name": "KYS_Q6",
"responses": {
"items": [
{
"code": 1,
"text": "Lied about forgetting my kit",
"element": "qdf:response"
},
{
"code": 2,
"text": "Lied about an injury",
"element": "qdf:response"
},
{
"code": 3,
"text": "Lied about feeling unwell",
"element": "qdf:response"
},
{
"code": 4,
"text": "Faked a note from my parents/ guardian",
"element": "qdf:response"
},
{
"code": 5,
"text": "Faked a note from my doctor/ health professional",
"element": "qdf:response"
}
],
"element": "qdf:response_group"
},
"element": "qdf:question",
"export": [
{
"name": "KYS_Q6"
}
]
},
{
"type": "single",
"options": {
"sort_order": "asending",
"chart_layout": "5",
"chart_type": "bar",
"chart_color": "green"
},
"text": "{multiple order=\"randomize\"} For the following question, please think about the teacher who has taught you P.E. MOST recently and if you have more than one teacher teaching you P.E. please think about the one who has taught you most often. <br/> Which of the following statements do you agree with? (Please tick all that apply)",
"name": "KYS_Q7",
"responses": {
"items": [
{
"code": 1,
"text": "My P.E. teacher inspires me to do more exercise",
"element": "qdf:response"
},
{
"code": 2,
"text": "My P.E. teacher motivates me to take part in P.E. lessons",
"element": "qdf:response"
},
{
"code": 3,
"text": "My P.E. teacher scares me",
"element": "qdf:response"
},
{
"code": 4,
"text": "My P.E. teacher makes P.E. boring",
"element": "qdf:response"
},
{
"code": 5,
"text": "My P.E. teacher makes P.E. fun",
"element": "qdf:response"
},
{
"code": 6,
"text": "My P.E. teacher makes P.E. difficult/ hard",
"element": "qdf:response"
}
],
"element": "qdf:response_group"
},
"element": "qdf:question",
"export": [
{
"name": "KYS_Q7"
}
]
},
{
"type": "single",
"options": {
"sort_order": "asending",
"chart_layout": "5",
"chart_type": "bar",
"chart_color": "green"
},
"text": "{multiple order=\"randomize\"} What would make you like P.E. more? (Please tick all that apply)",
"name": "KYS_Q8",
"responses": {
"items": [
{
"code": 1,
"text": "If the P.E. teacher was nicer to me",
"element": "qdf:response"
},
{
"code": 2,
"text": "If more lessons took place indoors (e.g. in the sports hall or a gym)",
"element": "qdf:response"
},
{
"code": 3,
"text": "If more lessons took place outdoors",
"element": "qdf:response"
},
{
"code": 4,
"text": "If we did more interesting sports/ activities",
"element": "qdf:response"
},
{
"code": 5,
"text": "If we had more choice of the types of sport we had to do",
"element": "qdf:response"
},
{
"code": 6,
"text": "If we could wear what we wanted for the lesson",
"element": "qdf:response"
},
{
"options": {
"fixed": true
},
"children": [
{
"export": [
{
"name": "KYS_Q8other"
}
],
"name": "KYS_Q8other",
"type": "open",
"element": "qdf:question"
}
],
"code": 7,
"text": "Other ",
"element": "qdf:response"
},
{
"options": {
"xor": true,
"fixed": true
},
"code": 8,
"text": "Don’t know",
"element": "qdf:response"
},
{
"options": {
"xor": true,
"fixed": true
},
"code": 9,
"text": "Not applicable – nothing would make me like P.E. more than I already do",
"element": "qdf:response"
}
],
"element": "qdf:response_group"
},
"element": "qdf:question",
"export": [
{
"name": "KYS_Q8"
}
]
}
],
"element": "qdf:page"
}
],
"element": "qdf:module"
},
{
"children": [
{
"children": [
{
"text": "\n",
"element": "qdf:text"
}
],
"element": "qdf:page"
}
],
"element": "qdf:module"
}
],
"panelid": 13,
"created": "#2014-01-10T15:57:18.594000+00:00#",
"typespec": {
"src": "/questionnaires/typespecs/initial.qdf",
"element": "qdf:typespec"
},
"qdf-ext:ext": [
"meaningful-page-names"
],
"element": "qdf:questionnaire",
"builtin": {
"src": "/questionnaires/builtins/initial.qdf",
"element": "qdf:typedef"
},
"committer": "majeed.sahebzadha",
"name": "Test_maj_demo_newG4_2",
"commit message": "added a new module within a module"
}
问题答案：
我将按以下方式进行处理：
def recursive(input, output=None):
if output is None:
output = {} # container to store results
if 'children' in input:
# do whatever, add things to output
recursive(input['children'], output)
return output
这样，output字典可用于所有深度的迭代，并return在最后包含所有内容。这意味着您不必显式处理return递归调用的值。
根据您所拥有的，它可能看起来像：
def recursive(input, output=None):
if output is None:
output = {} # container to store results
if 'children' in input:
for child in input['children']:
# do whatever, add things to output
recursive(child, output)
return output
并且output可以是不同的容器（例如list，set）。
