How to parse item from list in python

Question

How do I parse an item from the list in python?

I need to get a HOSTNAME from: {'Key': 'Name', 'Value': 'HOSTNAME'}

tag = [{'Key': 'Backup Initiator Rule', 'Value': 'Daily-6d-retention'}, 
        {'Key': 'delete_On', 'Value': '2019-08-31'},
        {'Key': 'Backup_Type', 'Value': 'Demo'},
        {'Key': 'Name', 'Value': 'HOSTNAME'},
        {'Key': 'Disaster_Recovery', 'Value': 'Full'}]

get tag["Tags"] then scan the list for a dictionary where Key == Name. Use ast.literal_eval on it first since it seems to be a string — Jean-François Fabre
– Jean-François Fabre ♦, Commented Aug 29, 2019 at 13:23
this appears to be a python dictionary written to string. why? can you change that? — Laurens Koppenol
– Laurens Koppenol, Commented Aug 29, 2019 at 13:25
but this string contains a "datetime.datetime" call... 'StartTime': datetime.datetime(2019, 8, 28, 13, 56, 8, 269000, tzinfo=tzutc()), — Jean-François Fabre
– Jean-François Fabre ♦, Commented Aug 29, 2019 at 13:28
i expect that that's not a call that's a datetime object's string representation — Laurens Koppenol
– Laurens Koppenol, Commented Aug 29, 2019 at 13:30

Narendra Kamatham · Accepted Answer · 2019-08-29 13:38:02Z

1

Try List Comp:

tag = "[{'Key': 'Backup Initiator Rule', 'Value': 'Daily-6d-retention'}, {'Key': 'delete_On', 'Value': '2019-08-31'},{'Key': 'Backup_Type', 'Value': 'Demo'},{'Key': 'Name', 'Value': 'HOSTNAME'},{'Key': 'Disaster_Recovery', 'Value': 'Full'}]"

print([dic['Value'] for dic in eval(tag) if dic['Key']=='Name'])

Results: ['HOSTNAME']

answered Aug 29, 2019 at 13:38

Narendra Kamatham

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3 Comments

Orest Gulman Over a year ago

how to be in case if the type of variable 'tag' is class 'list'

Orest Gulman Over a year ago

tag = [{'Key': 'Backup Initiator Rule', 'Value': 'Daily-6d-retention'}, {'Key': 'delete_On', 'Value': '2019-08-31'},{'Key': 'Backup_Type', 'Value': 'Demo'},{'Key': 'Name', 'Value': 'HOSTNAME'},{'Key': 'Disaster_Recovery', 'Value': 'Full'}]

Narendra Kamatham Over a year ago

Just change "eval(tag)" to tag.

Laurens Koppenol · Accepted Answer · 2019-08-29 13:34:50Z

1

Regex

Since this is not parseable json i would go for the regex way:

import re
re.findall("{'Key': 'Name', 'Value': '(.*?)'}", tag)

This returns a list of all objects found:

['HOSTNAME']

Edit OP changed the tag string, this might not be the best option now.

edited Aug 29, 2019 at 13:34

answered Aug 29, 2019 at 13:28

Laurens Koppenol

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Comments

Ahndwoo · Accepted Answer · 2019-08-29 15:00:12Z

0

for dict in tag:
    if dict['Key'] == 'Name':
        hostname = dict['Value']
        break

edited Aug 29, 2019 at 15:00

answered Aug 29, 2019 at 13:30

Ahndwoo

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1 Comment

Orest Gulman Over a year ago

I meant list <class 'list'>

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