[英]Python REGEX: remove $ and Curly Brackets from string elements if string element is prefixed by $
在 Python 筆記本中,我有一個想要以特定方式解析的字符串,但我無法找出必要的正則表達式。 這並不重要,但該字符串之前是一個復雜的嵌套字典,該字典源自通過 json 方法將 Oozie 工作流 xml 轉換為 Python 字典。
'{"workflow-app": {"@xmlns": "uri:oozie:workflow:0.4", "@name": "simple-Workflow", "start": {"@to": "Create_External_Table"}, "action": [{"@name": "Create_External_Table", "hive": {"@xmlns": "uri:oozie:hive-action:0.4", "job-tracker": "${xyz.com:8088}", "name-node": "${hdfs://rootname}", "script": "${hdfs_path_of_script/external.hive}"}, "ok": {"@to": "Create_orc_Table"}, "error": {"@to": "kill_job"}}, {"@name": "Create_orc_Table", "hive": {"@xmlns": "uri:oozie:hive-action:0.4", "job-tracker": "${xyz.com:8088}", "name-node": "${hdfs://rootname}", "script": "${hdfs_path_of_script/orc.hive}"}, "ok": {"@to": "Insert_into_Table"}, "error": {"@to": "kill_job"}}, {"@name": "Insert_into_Table", "hive": {"@xmlns": "uri:oozie:hive-action:0.4", "job-tracker": "${xyz.com:8088}", "name-node": "${hdfs://rootname}", "script": "${hdfs_path_of_script/Copydata.hive}", "param": "${database_name}"}, "ok": {"@to": "end"}, "error": {"@to": "kill_job"}}], "kill": {"@name": "kill_job", "message": "Job failed"}, "end": {"@name": "end"}}}'
無論哪種情況,您都會注意到字符串中的某些元素以美元符號為前綴。 例如“${xyz.com:8088}”、“${hdfs_path_of_script/external.hive}”等等。
其他元素也由花括號包裹,但對於那些且只有那些以美元符號為前綴的元素,我想刪除美元符號前綴和立即包裹它的花括號。
在上面的兩個例子中,我想獲取“xyz.com:8088”和“hdfs_path_of_script/external.hive”。 這就是字符串最終的樣子。
'{"workflow-app": {"@xmlns": "uri:oozie:workflow:0.4", "@name": "simple-Workflow", "start": {"@to": "Create_External_Table"}, "action": [{"@name": "Create_External_Table", "hive": {"@xmlns": "uri:oozie:hive-action:0.4", "job-tracker": "xyz.com:8088", "name-node": "hdfs://rootname", "script": "hdfs_path_of_script/external.hive"}, "ok": {"@to": "Create_orc_Table"}, "error": {"@to": "kill_job"}}, {"@name": "Create_orc_Table", "hive": {"@xmlns": "uri:oozie:hive-action:0.4", "job-tracker": "xyz.com:8088", "name-node": "hdfs://rootname", "script": "hdfs_path_of_script/orc.hive"}, "ok": {"@to": "Insert_into_Table"}, "error": {"@to": "kill_job"}}, {"@name": "Insert_into_Table", "hive": {"@xmlns": "uri:oozie:hive-action:0.4", "job-tracker": "xyz.com:8088", "name-node": "hdfs://rootname", "script": "hdfs_path_of_script/Copydata.hive", "param": "database_name"}, "ok": {"@to": "end"}, "error": {"@to": "kill_job"}}], "kill": {"@name": "kill_job", "message": "Job failed"}, "end": {"@name": "end"}}}'
有人可以幫我解析這個東西嗎? 如果重要的話,我正在使用 Python 3.7。
您可以使用遞歸來遍歷字典並更改適當的值:
import re
import json
pat = re.compile(r"\$\{(.*)\}")
def transform(d):
if isinstance(d, dict):
for k, v in d.items():
if isinstance(v, str):
d[k] = pat.sub(r"\1", v)
else:
transform(v)
elif isinstance(d, list):
for v in d:
transform(v)
s = '{"workflow-app": {"@xmlns": "uri:oozie:workflow:0.4", "@name": "simple-Workflow", "start": {"@to": "Create_External_Table"}, "action": [{"@name": "Create_External_Table", "hive": {"@xmlns": "uri:oozie:hive-action:0.4", "job-tracker": "${xyz.com:8088}", "name-node": "${hdfs://rootname}", "script": "${hdfs_path_of_script/external.hive}"}, "ok": {"@to": "Create_orc_Table"}, "error": {"@to": "kill_job"}}, {"@name": "Create_orc_Table", "hive": {"@xmlns": "uri:oozie:hive-action:0.4", "job-tracker": "${xyz.com:8088}", "name-node": "${hdfs://rootname}", "script": "${hdfs_path_of_script/orc.hive}"}, "ok": {"@to": "Insert_into_Table"}, "error": {"@to": "kill_job"}}, {"@name": "Insert_into_Table", "hive": {"@xmlns": "uri:oozie:hive-action:0.4", "job-tracker": "${xyz.com:8088}", "name-node": "${hdfs://rootname}", "script": "${hdfs_path_of_script/Copydata.hive}", "param": "${database_name}"}, "ok": {"@to": "end"}, "error": {"@to": "kill_job"}}], "kill": {"@name": "kill_job", "message": "Job failed"}, "end": {"@name": "end"}}}'
data = json.loads(s)
transform(data)
print(json.dumps(data, indent=4))
印刷:
{
"workflow-app": {
"@xmlns": "uri:oozie:workflow:0.4",
"@name": "simple-Workflow",
"start": {
"@to": "Create_External_Table"
},
"action": [
{
"@name": "Create_External_Table",
"hive": {
"@xmlns": "uri:oozie:hive-action:0.4",
"job-tracker": "xyz.com:8088",
"name-node": "hdfs://rootname",
"script": "hdfs_path_of_script/external.hive"
},
"ok": {
"@to": "Create_orc_Table"
},
"error": {
"@to": "kill_job"
}
},
{
"@name": "Create_orc_Table",
"hive": {
"@xmlns": "uri:oozie:hive-action:0.4",
"job-tracker": "xyz.com:8088",
"name-node": "hdfs://rootname",
"script": "hdfs_path_of_script/orc.hive"
},
"ok": {
"@to": "Insert_into_Table"
},
"error": {
"@to": "kill_job"
}
},
{
"@name": "Insert_into_Table",
"hive": {
"@xmlns": "uri:oozie:hive-action:0.4",
"job-tracker": "xyz.com:8088",
"name-node": "hdfs://rootname",
"script": "hdfs_path_of_script/Copydata.hive",
"param": "database_name"
},
"ok": {
"@to": "end"
},
"error": {
"@to": "kill_job"
}
}
],
"kill": {
"@name": "kill_job",
"message": "Job failed"
},
"end": {
"@name": "end"
}
}
}
我可能會加載json
並處理數據,但是這個正則表達式可以滿足您的要求:
import re
# your original JSON
ins = '{"workflow-app": {"@xmlns": "uri:oozie:workflow:0.4", "@name": "simple-Workflow", "start": {"@to": "Create_External_Table"}, "action": [{"@name": "Create_External_Table", "hive": {"@xmlns": "uri:oozie:hive-action:0.4", "job-tracker": "${xyz.com:8088}", "name-node": "${hdfs://rootname}", "script": "${hdfs_path_of_script/external.hive}"}, "ok": {"@to": "Create_orc_Table"}, "error": {"@to": "kill_job"}}, {"@name": "Create_orc_Table", "hive": {"@xmlns": "uri:oozie:hive-action:0.4", "job-tracker": "${xyz.com:8088}", "name-node": "${hdfs://rootname}", "script": "${hdfs_path_of_script/orc.hive}"}, "ok": {"@to": "Insert_into_Table"}, "error": {"@to": "kill_job"}}, {"@name": "Insert_into_Table", "hive": {"@xmlns": "uri:oozie:hive-action:0.4", "job-tracker": "${xyz.com:8088}", "name-node": "${hdfs://rootname}", "script": "${hdfs_path_of_script/Copydata.hive}", "param": "${database_name}"}, "ok": {"@to": "end"}, "error": {"@to": "kill_job"}}], "kill": {"@name": "kill_job", "message": "Job failed"}, "end": {"@name": "end"}}}'
# this is your expected output string
outs = '{"workflow-app": {"@xmlns": "uri:oozie:workflow:0.4", "@name": "simple-Workflow", "start": {"@to": "Create_External_Table"}, "action": [{"@name": "Create_External_Table", "hive": {"@xmlns": "uri:oozie:hive-action:0.4", "job-tracker": "xyz.com:8088", "name-node": "hdfs://rootname", "script": "hdfs_path_of_script/external.hive"}, "ok": {"@to": "Create_orc_Table"}, "error": {"@to": "kill_job"}}, {"@name": "Create_orc_Table", "hive": {"@xmlns": "uri:oozie:hive-action:0.4", "job-tracker": "xyz.com:8088", "name-node": "hdfs://rootname", "script": "hdfs_path_of_script/orc.hive"}, "ok": {"@to": "Insert_into_Table"}, "error": {"@to": "kill_job"}}, {"@name": "Insert_into_Table", "hive": {"@xmlns": "uri:oozie:hive-action:0.4", "job-tracker": "xyz.com:8088", "name-node": "hdfs://rootname", "script": "hdfs_path_of_script/Copydata.hive", "param": "database_name"}, "ok": {"@to": "end"}, "error": {"@to": "kill_job"}}], "kill": {"@name": "kill_job", "message": "Job failed"}, "end": {"@name": "end"}}}'
# replace strings that...
# * start with a "
# * then has '${'
# * capture non-greedy arbitrary number of characters with (.*?)
# * then has '}'
# * then ends with "
# Replace it with the capture in \1 and surround with quotes
subbed = re.sub(r'"\${(.*?)}"', r'"\1"', ins)
print(subbed == outs)
# this output True
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