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[英]Translate key-value string with arrays into json object in python
[英]Python Script to filter arrays containing a specific value in JSON object
我有一个json对象,它由一个带有键'data'的对象组成,它有一组数组中列出的值。 我需要返回包含值x的所有数组,但数组本身没有键。 我正在尝试编写一个脚本来输入源文件(inFile)和一个定义导出文件(outFile)。 这是我的数据结构:
{ "data": [
["x", 1, 4, 6, 2, 7],
["y", 3, 2, 5, 8, 4],
["z", 5, 2, 5, 9, 9],
["x", 3, 7, 2, 6, 8]
]
}
这是我目前的脚本:
import json
def jsonFilter( inFile, outFile ):
out = None;
with open( inFile, 'r') as jsonFile:
d = json.loads(json_data)
a = d['data']
b = [b for b in a if b != 'x' ]
del b
out = a
if out:
with open( outFile, 'w' ) as jsonFile:
jsonFile.write( json.dumps( out ) );
else:
print "Error creating new jsonFile!"
解
感谢Rob和大家的帮助! 这是最终的工作命令行工具。 这需要两个参数:inFile和Outfile。 〜$ python jsonFilter.py inFile.json outFile.json
import json
def jsonFilter( inFile, outFile ):
# make a dictionary.
out = {};
with open( inFile, 'r') as jsonFile:
json_data = jsonFile.read()
d = json.loads(json_data)
# build the data you want to save to look like the original
# by taking the data in the d['data'] element filtering what you want
# elements where b[0] is 'x'
out['data'] = [b for b in d['data'] if b[0] == 'x' ]
if out:
with open( outFile, 'w' ) as jsonFile:
jsonFile.write( json.dumps( out ) );
else:
print "Error creating new JSON file!"
if __name__ == "__main__":
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('inFile', nargs=1, help="Choose the in file to use")
parser.add_argument('outFile', nargs=1, help="Choose the out file to use")
args = parser.parse_args()
jsonFilter( args.inFile[0] , args.outFile[0] );
第一个问题查询字符串对于所有内容都是真的(也就是说,因为你将b(列表)与'x'比较为字符串,所以返回整个数据集
b = [b for b in a if b != 'x' ]
你想做的是:
b = [b for b in a if b[0] != 'x' ]
第二个问题是您尝试通过查询和删除结果来删除数据。 由于结果包含不会从原始容器中删除任何内容的副本。
而是仅使用您想要的元素构建新数据,并保存它们。 此外,您没有在out数据中重新创建'data'元素,因此json使输出具有与输入数据相同的结构。
import json
def jsonFilter( inFile, outFile ):
# make a dictionary instead.
out = {};
with open( inFile, 'r') as jsonFile:
json_data = jsonFile.read()
d = json.loads(json_data)
# build the data you want to save to look like the original
# by taking the data in the d['data'] element filtering what you want
# elements where b[0] is 'x'
out['data'] = [b for b in d['data'] if b[0] == 'x' ]
if out:
with open( outFile, 'w' ) as jsonFile:
jsonFile.write( json.dumps( out ) );
else:
print "Error creating new jsonFile!"
输出json数据看起来像:
'{"data": [["x", 1, 4, 6, 2, 7], ["x", 3, 7, 2, 6, 8]]}'
如果您不希望输出具有'data'根元素,而只需要与您的过滤器匹配的数据数组,则更改该行:
out['data'] = [b for b in d['data'] if b[0] == 'x' ]
至
out = [b for b in d['data'] if b[0] == 'x' ]
通过此更改,输出json数据如下所示:
'[["x", 1, 4, 6, 2, 7], ["x", 3, 7, 2, 6, 8]]'
所以,基本上你想要过滤掉包含第一个元素是'x'的数组的输入数据,可能这样做:
import json
def jsonFilter(inFile, outFile):
with open(inFile, 'r') as jsonFile:
d = json.loads(json_data)
out = {
'data': filter(lambda x: x[0] == 'x', d['data'])
}
if out['data']:
with open(outFile, 'w') as jsonFile:
jsonFile.write(json.dumps(out))
else:
print "Error creating new jsonFile!"
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