Python array: get index by element value

Question

A have an array like this

{  
    "records":[  
        {  
            "domain":"example.com",
            "fqdn":"111",
        },
        {  
            "domain":"example.com",
            "fqdn":"2222",
        },
        {  
            "domain":"example.com",
            "fqdn":"333",
        },
    ],
}

How can I get index of element with fqdn == "333"?

I know, that I can use for, but I hope, that there is another way — Alexey Berezuev
– Alexey Berezuev, Commented Feb 12, 2015 at 9:33
I'm wondering why you need this index in the first place. Can you tell us more - most probably, there's a better way. — georg
– georg, Commented Feb 12, 2015 at 9:44

Ben · Accepted Answer · 2015-02-12 09:46:14Z

3

You can use a list comprehension with enumerate:

[x for x, y in enumerate(data['records']) if y['fqdn'] == '333'][0]

You'd have to catch IndexError for the case where it didn't exist, though.

As suggested in the comments, you could avoid the issues of redundant lookups for duplicate target values, and catching IndexError, by using a generator and next:

next((x for x, y in enumerate(data['records']) if y['fqdn'] == '333'), None)

edited Feb 12, 2015 at 9:46

answered Feb 12, 2015 at 9:34

Ben

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2 Comments

volcano Over a year ago

If there's more than one target value, your code will make redundant lookups.

georg Over a year ago

You can also use a generator expr instead of a comp, next((...), None) thus avoiding an exception and the problem in the ^^^ comment.

Avinash Raj · Accepted Answer · 2015-02-12 09:37:39Z

1

Seems like you want something like this,

>>> d = {  
    "records":[  
        {  
            "domain":"example.com",
            "fqdn":"111",
        },
        {  
            "domain":"example.com",
            "fqdn":"2222",
        },
        {  
            "domain":"example.com",
            "fqdn":"333",
        },
    ],
}
>>> for i in d.values():
        for s,m in enumerate(i):
            if m['fqdn'] == "333":
                print(s)


2

answered Feb 12, 2015 at 9:37

Avinash Raj

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Comments

Haresh Shyara · Accepted Answer · 2015-02-12 10:03:14Z

0

li = list(di['records'])
for x in li:
    for k, v in x.items():
        if v == '333':
            print k, v

answered Feb 12, 2015 at 10:03

Haresh Shyara

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1 Comment

Makyen Over a year ago

Usually it is helpful to include some text which explains how the code answers the question or solves the problem in addition to bare code.

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