生成动态嵌套JSON对象和数组 - python

Question

由于问题解释了问题,我一直在尝试生成嵌套的JSON对象.在这种情况下,我有for循环从字典中获取数据dic.以下是代码:

f = open("test_json.txt", 'w')
flag = False
temp = ""
start = "{\n\t\"filename\"" + " : \"" +initial_filename+"\",\n\t\"data\"" +" : " +" [\n"
end = "\n\t]" +"\n}"
f.write(start)
for i, (key,value) in enumerate(dic.iteritems()):
    f.write("{\n\t\"keyword\":"+"\""+str(key)+"\""+",\n")
    f.write("\"term_freq\":"+str(len(value))+",\n")
    f.write("\"lists\":[\n\t")
    for item in value:
        f.write("{\n")
        f.write("\t\t\"occurance\" :"+str(item)+"\n")
        #Check last object
        if value.index(item)+1 == len(value):
            f.write("}\n" 
            f.write("]\n")
        else:
            f.write("},") # close occurrence object
    # Check last item in dic
    if i == len(dic)-1:
        flag = True
    if(flag):
        f.write("}")
    else:
        f.write("},") #close lists object
        flag = False 

#check for flag
f.write("]") #close lists array 
f.write("}")

预期产出是:

{
"filename": "abc.pdf",
"data": [{
    "keyword": "irritation",
    "term_freq": 5,
    "lists": [{
        "occurance": 1
    }, {
        "occurance": 1
    }, {
        "occurance": 1
    }, {
        "occurance": 1
    }, {
        "occurance": 2
    }]
}, {
    "keyword": "bomber",
    "lists": [{
        "occurance": 1
    }, {
        "occurance": 1
    }, {
        "occurance": 1
    }, {
        "occurance": 1
    }, {
        "occurance": 2
    }],
    "term_freq": 5
}]
}

但目前我得到的输出如下:

{
"filename": "abc.pdf",
"data": [{
    "keyword": "irritation",
    "term_freq": 5,
    "lists": [{
        "occurance": 1
    }, {
        "occurance": 1
    }, {
        "occurance": 1
    }, {
        "occurance": 1
    }, {
        "occurance": 2
    },]                // Here lies the problem "," before array(last element)
}, {
    "keyword": "bomber",
    "lists": [{
        "occurance": 1
    }, {
        "occurance": 1
    }, {
        "occurance": 1
    }, {
        "occurance": 1
    }, {
        "occurance": 2
    },],                  // Here lies the problem "," before array(last element)
    "term_freq": 5
}]
}

请帮助,我试图解决它,但失败了.请不要将其标记为重复,因为我已经检查了其他答案并且根本没有帮助.

编辑1: 输入基本上取自字典,dic其映射类型<String, List> 为例如:"irritation"=> [1,3,5,7,8]其中激怒是关键,并映射到页码列表.这基本上在外部for循环中读取,其中key是关键字,value是该关键字出现的页面列表.

编辑2:

dic = collections.defaultdict(list) # declaring the variable dictionary
dic[key].append(value) # inserting the values - useless to tell here
for key in dic:
    # Here dic[x] represents list - each value of x
    print key,":",dic[x],"\n" #prints the data in dictionary

Answer 1

@ andrea-f对我来说很好,这里是另一个解决方案:

随意挑选两个:)

import json

dic = {
        "bomber": [1, 2, 3, 4, 5],
        "irritation": [1, 3, 5, 7, 8]
      }

filename = "abc.pdf"

json_dict = {}
data = []

for k, v in dic.iteritems():
  tmp_dict = {}
  tmp_dict["keyword"] = k
  tmp_dict["term_freq"] = len(v)
  tmp_dict["lists"] = [{"occurrance": i} for i in v]
  data.append(tmp_dict)

json_dict["filename"] = filename
json_dict["data"] = data

with open("abc.json", "w") as outfile:
    json.dump(json_dict, outfile, indent=4, sort_keys=True)

这是同样的想法,我首先创建一个json_dict直接在json中保存的大.我使用with语句来保存json,避免捕获exception

此外,您应该查看文档,了解json.dumps()您的json输出是否需要进一步改进.

编辑

只是为了好玩,如果你不喜欢tmpvar,你可以for在一行中完成所有的数据循环:)

json_dict["data"] = [{"keyword": k, "term_freq": len(v), "lists": [{"occurrance": i} for i in v]} for k, v in dic.iteritems()]

它可以为最终解决方案提供一些不完全可读的东西:

import json

json_dict = {
              "filename": "abc.pdf",
              "data": [{
                        "keyword": k,
                        "term_freq": len(v),
                        "lists": [{"occurrance": i} for i in v]
                       } for k, v in dic.iteritems()]
            }

with open("abc.json", "w") as outfile:
    json.dump(json_dict, outfile, indent=4, sort_keys=True)

编辑2

看起来你不想将你json的输出保存为所需的输出,但是能够阅读它.

实际上,您也可以使用json.dumps()以打印您的json.

with open('abc.json', 'r') as handle:
    new_json_dict = json.load(handle)
    print json.dumps(json_dict, indent=4, sort_keys=True)

还有这里人们问题,但,"filename":是在列表的末尾印,因为d的data到来之前的f.

要强制执行命令,您必须OrderedDict在dict的生成中使用.小心语法是丑陋的(imo)python 2.X

这是新的完整解决方案;)

import json
from collections import OrderedDict

dic = {
        'bomber': [1, 2, 3, 4, 5],
        'irritation': [1, 3, 5, 7, 8]
      }

json_dict = OrderedDict([
              ('filename', 'abc.pdf'),
              ('data', [ OrderedDict([
                                        ('keyword', k),
                                        ('term_freq', len(v)),
                                        ('lists', [{'occurrance': i} for i in v])
                                     ]) for k, v in dic.iteritems()])
            ])

with open('abc.json', 'w') as outfile:
    json.dump(json_dict, outfile)


# Now to read the orderer json file

with open('abc.json', 'r') as handle:
    new_json_dict = json.load(handle, object_pairs_hook=OrderedDict)
    print json.dumps(json_dict, indent=4)

将输出:

{
    "filename": "abc.pdf", 
    "data": [
        {
            "keyword": "bomber", 
            "term_freq": 5, 
            "lists": [
                {
                    "occurrance": 1
                }, 
                {
                    "occurrance": 2
                }, 
                {
                    "occurrance": 3
                }, 
                {
                    "occurrance": 4
                }, 
                {
                    "occurrance": 5
                }
            ]
        }, 
        {
            "keyword": "irritation", 
            "term_freq": 5, 
            "lists": [
                {
                    "occurrance": 1
                }, 
                {
                    "occurrance": 3
                }, 
                {
                    "occurrance": 5
                }, 
                {
                    "occurrance": 7
                }, 
                {
                    "occurrance": 8
                }
            ]
        }
    ]
}

但要小心,大多数情况下,最好保存常规 .json文件以便成为跨语言.