如何从一个json文件中获取数据

Question

我有多个来自json的文本，例如

{"citationID":"a1u01nqrgpa","properties":{"formattedCitation":"[2]","plainCitation":"[2]","noteIndex":0},"citationItems":[{"id":44,"uris":["http://zotero.org/users/local/sIEziHS8/items/VR3UIAUH"],"uri":["http://zotero.org/users/local/sIEziHS8/items/VR3UIAUH"],"itemData":{"id":44,"type":"article-journal","title":"Bacillus subtilis and its relatives: molecular biological and industrial workhorses","container-title":"Trends in biotechnology","page":"247–256","volume":"10","source":"Google Scholar","title-short":"Bacillus subtilis and its relatives","author":[{"family":"Harwood","given":"Colin R."}],"issued":{"date-parts":[["1992"]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} 

{"citationID":"a2k9krb4sun","properties":{"formattedCitation":"[7]","plainCitation":"[7]","noteIndex":0},"citationItems":[{"id":76,"uris":["http://zotero.org/users/local/sIEziHS8/items/KAHC7LAC"],"uri":["http://zotero.org/users/local/sIEziHS8/items/KAHC7LAC"],"itemData":{"id":76,"type":"article-journal","title":"Development of Pgrac100-based expression vectors allowing high protein production levels in Bacillus subtilis and relatively low basal expression in Escherichia coli","container-title":"Microbial Cell Factories","volume":"14","issue":"1","source":"Crossref","URL":"http://www.microbialcellfactories.com/content/14/1/72","DOI":"10.1186/s12934-015-0255-z","ISSN":"1475-2859","language":"en","author":[{"family":"Phan","given":"Trang Thi Phuong"},{"family":"Tran","given":"Linh Thuoc"},{"family":"Schumann","given":"Wolfgang"},{"family":"Nguyen","given":"Hoang Duc"}],"issued":{"date-parts":[["2015",12]]},"accessed":{"date-parts":[["2018",12,14]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} 

{"citationID":"a13g93on8ud","properties":{"formattedCitation":"[6]","plainCitation":"[6]","noteIndex":0},"citationItems":[{"id":75,"uris":["http://zotero.org/users/local/sIEziHS8/items/WN9Q3G27"],"uri":["http://zotero.org/users/local/sIEziHS8/items/WN9Q3G27"],"itemData":{"id":75,"type":"article-journal","title":"Construction of a 5′-controllable stabilizing element (CoSE) for over-production of heterologous proteins at high levels in Bacillus subtilis","container-title":"Journal of Biotechnology","page":"32-39","volume":"168","issue":"1","source":"Crossref","DOI":"10.1016/j.jbiotec.2013.07.031","ISSN":"01681656","language":"en","author":[{"family":"Phan","given":"Trang Thi Phuong"},{"family":"Nguyen","given":"Hoang Duc"},{"family":"Schumann","given":"Wolfgang"}],"issued":{"date-parts":[["2013",10]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} 

{"citationID":"ajlpfebik","properties":{"formattedCitation":"[13]","plainCitation":"[13]","noteIndex":0},"citationItems":[{"id":6,"uris":["http://zotero.org/users/local/sIEziHS8/items/IWPBWYVL"],"uri":["http://zotero.org/users/local/sIEziHS8/items/IWPBWYVL"],"itemData":{"id":6,"type":"article-journal","title":"Use of the Escherichia coli lac repressor and operator to control gene expression in Bacillus subtilis","container-title":"Proceedings of the National Academy of Sciences","page":"439-443","volume":"81","issue":"2","source":"www.pnas.org","abstract":"The Escherichia coli lac operator has been placed on the 3' side of the promoter for the penicillinase gene of Bacillus licheniformis, creating a hybrid promoter controllable by the E. coli lac repressor. The E. coli lac repressor gene has been placed under the control of a promoter and ribosome-binding site that allows expression in Bacillus subtilis. When the penicillinase gene that contains the lac operator is expressed in B. subtilis on a plasmid that also produces the lac repressor, the expression of the penicillinase gene can be modulated by isopropyl beta-D-thiogalactoside (IPTG), an inducer of the lac operon in E. coli. A similar system was constructed from a promoter of the B. subtilis phage SPO-1 and the leukocyte interferon A gene, which allowed the controlled expression of interferon in B. subtilis. These two examples show that a functional control system can be introduced into B. subtilis from E. coli.","ISSN":"0027-8424, 1091-6490","note":"PMID: 6420789","journalAbbreviation":"PNAS","language":"en","author":[{"family":"Yansura","given":"D. G."},{"family":"Henner","given":"D. J."}],"issued":{"date-parts":[["1984",1,1]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} 

我需要从每个json中获取标题（4个标题）。

我尝试了这段代码

import json
import uuid

with open('1.json') as f:
    contents = json.load(f)
i = 0
while i < 25:
        i += 1
        if 'title' in contents['citationItems'][$i]['itemData']:
                print 'title    = ' + '"' + contents['citationItems'][0]['itemData']['title'] + '",'

但未能获得结果错误：

  File "stack.py", line 9
    if 'title' in contents['citationItems'][$i]['itemData']:
                                            ^
SyntaxError: invalid syntax

我需要像这样的结果

title    = "a"
title    = "b"
title    = "c"
title    = "d"

Answer 1

您必须以pythonic方式编写：

if 'title' in contents['citationItems'][i]['itemData']:
   print 'title    = ' + '"' + contents['citationItems'][0]['itemData']['title'] + '",'

从if 'title' in contents['citationItems'][$i]['itemData']:删除“ $”

编辑：

创建json文件，例如：

{
    "data" : [
        {"citationID":"a1u01nqrgpa","properties":{"formattedCitation":"[2]","plainCitation":"[2]",
        "noteIndex":0},"citationItems":[{"id":44,"uris":["http://zotero.org/users/local/sIEziHS8/items/VR3UIAUH"],
            "uri":["http://zotero.org/users/local/sIEziHS8/items/VR3UIAUH"],"itemData":{"id":44,"type":"article-journal",
                "title":"Bacillus subtilis and its relatives: molecular biological and industrial workhorses","container-title"
                :"Trends in biotechnology","page":"247–256","volume":"10","source":"Google Scholar","title-short":
                "Bacillus subtilis and its relatives","author":[{"family":"Harwood","given":"Colin R."}],
                "issued":{"date-parts":[["1992"]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} ,

{"citationID":"a2k9krb4sun","properties":{"formattedCitation":"[7]","plainCitation":"[7]","noteIndex":0},
"citationItems":[{"id":76,"uris":["http://zotero.org/users/local/sIEziHS8/items/KAHC7LAC"],"uri":["http://zotero.org/users/local/sIEziHS8/items/KAHC7LAC"],"itemData":{"id":76,"type":"article-journal","title":"Development of Pgrac100-based expression vectors allowing high protein production levels in Bacillus subtilis and relatively low basal expression in Escherichia coli","container-title":"Microbial Cell Factories","volume":"14","issue":"1","source":"Crossref","URL":"http://www.microbialcellfactories.com/content/14/1/72","DOI":"10.1186/s12934-015-0255-z","ISSN":"1475-2859","language":"en","author":[{"family":"Phan","given":"Trang Thi Phuong"},{"family":"Tran","given":"Linh Thuoc"},{"family":"Schumann","given":"Wolfgang"},{"family":"Nguyen","given":"Hoang Duc"}],"issued":{"date-parts":[["2015",12]]},"accessed":{"date-parts":[["2018",12,14]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} ,

{"citationID":"a13g93on8ud","properties":{"formattedCitation":"[6]","plainCitation":"[6]","noteIndex":0},
"citationItems":[{"id":75,"uris":["http://zotero.org/users/local/sIEziHS8/items/WN9Q3G27"],"uri":["http://zotero.org/users/local/sIEziHS8/items/WN9Q3G27"],"itemData":{"id":75,"type":"article-journal","title":"Construction of a 5′-controllable stabilizing element (CoSE) for over-production of heterologous proteins at high levels in Bacillus subtilis","container-title":"Journal of Biotechnology","page":"32-39","volume":"168","issue":"1","source":"Crossref","DOI":"10.1016/j.jbiotec.2013.07.031","ISSN":"01681656","language":"en","author":[{"family":"Phan","given":"Trang Thi Phuong"},{"family":"Nguyen","given":"Hoang Duc"},{"family":"Schumann","given":"Wolfgang"}],"issued":{"date-parts":[["2013",10]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} ,

{"citationID":"ajlpfebik","properties":{"formattedCitation":"[13]","plainCitation":"[13]","noteIndex":0},
"citationItems":[{"id":6,"uris":["http://zotero.org/users/local/sIEziHS8/items/IWPBWYVL"],
    "uri":["http://zotero.org/users/local/sIEziHS8/items/IWPBWYVL"],"itemData":{"id":6,"type":"article-journal",
        "title":"Use of the Escherichia coli lac repressor and operator to control gene expression in Bacillus subtilis","container-title":"Proceedings of the National Academy of Sciences","page":"439-443","volume":"81","issue":"2","source":"www.pnas.org","abstract":"The Escherichia coli lac operator has been placed on the 3' side of the promoter for the penicillinase gene of Bacillus licheniformis, creating a hybrid promoter controllable by the E. coli lac repressor. The E. coli lac repressor gene has been placed under the control of a promoter and ribosome-binding site that allows expression in Bacillus subtilis. When the penicillinase gene that contains the lac operator is expressed in B. subtilis on a plasmid that also produces the lac repressor, the expression of the penicillinase gene can be modulated by isopropyl beta-D-thiogalactoside (IPTG), an inducer of the lac operon in E. coli. A similar system was constructed from a promoter of the B. subtilis phage SPO-1 and the leukocyte interferon A gene, which allowed the controlled expression of interferon in B. subtilis. These two examples show that a functional control system can be introduced into B. subtilis from E. coli.","ISSN":"0027-8424, 1091-6490","note":"PMID: 6420789","journalAbbreviation":"PNAS","language":"en","author":[{"family":"Yansura","given":"D. G."},{"family":"Henner","given":"D. J."}],"issued":{"date-parts":[["1984",1,1]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} 
]
}

并更改.py文件：

import json
import uuid

with open('1.json') as f:
    contents = json.load(f)

for data in contents['data']:
    if 'title' in data['citationItems'][0]['itemData']:
        print('title    = ' + '"' + data['citationItems'][0]['itemData']['title'] + '",')

O / P

title    = "Bacillus subtilis and its relatives: molecular biological and industrial workhorses",
title    = "Development of Pgrac100-based expression vectors allowing high protein production levels in Bacillus subtilis and relatively low basal expression in Escherichia coli",
title    = "Construction of a 5′-controllable stabilizing element (CoSE) for over-production of heterologous proteins at high levels in Bacillus subtilis",
title    = "Use of the Escherichia coli lac repressor and operator to control gene expression in Bacillus subtilis",

Answer 2

Python倾向于使用更简单的路径。 我们没有用于变量的$ ，这是Shell脚本（由Perl和PHP继承）。 我们通常避免迭代索引。 而且进行额外的检查而不是失败很容易出错，因为我们可以看到您似乎在同一位置使用$i和0 。 此外， 格式字符串支持层次结构引用。

for citationItem in contents['citationItems']:
    print('title     = "{0[itemData][title]}"'.format(citationItem))

如果我们可能遇到缺少标题的citationItem，则跳过它会更容易，但有一个例外：

for citationItem in contents['citationItems']:
    try:
        print('title     = "{0[itemData][title]}"'.format(citationItem))
    except KeyError:
        pass