CODEWITHSUNDEEP
pythonloopsdictionary
user685018
user685018

Reputation:

Creating multi-level dictionary from string [Python]

I'm creating a mail "bot" for one of my web services that will periodically collect a queue of e-mail messages to be sent from a PHP script and send them via Google's SMTP servers. The PHP script returns the messages in this format:

[email protected]:Full Name:shortname\[email protected]:Another Full Name:anothershortname\[email protected]:Foo:bar

I need to "convert" that into something like this:

{
    "[email protected]": [
        [
            "Full Name",
            "shortname"
        ],
        [
            "Foo",
            "bar"
        ]
    ],
    "[email protected]": [
        [
            "Another Full Name",
            "anothershortname"
        ]
    ]
}

Notice I need to have only one key per e-mail, even if there are multiple instances of an address. I know I can probably do it with two consecutive loops, one to build the first level of the dictionary and the second to populate it, but there should be a way to do it in one shot. This is my code so far:

raw = "[email protected]:Full Name:shortname\[email protected]:Another Full Name:anothershortname\[email protected]:Foo:bar"

print raw

newlines = raw.split("\n")

print newlines

merged = {}
for message in newlines:
    message = message.split(":")
    merged[message[0]].append([message[1], message[2]])

print merged

I'm getting a KeyError on the last line of the loop, which I take to mean the key has to exist before appending anything to it (appending to a nonexistent key will not create that key).

I'm new to Python and not really familiar with lists and dictionaries yet, so your help is much appreciated!

Upvotes: 2

Views: 2642

Answers (4)

Rik Poggi
Rik Poggi

Reputation: 29302

I see that you've already accepted an answer, but maybe you're anyhow interested that what you're doing can be easily achieved with defaultdict:

from collections import defaultdict
raw = "[email protected]:Full Name:shortname\[email protected]:Another Full Name:anothershortname\[email protected]:Foo:bar"

merged = defaultdict(list)
for line in raw.split('\n'):
    line = line.split(':')
    merged[line[0]].append(line[1:])

Upvotes: 1

Abhranil Das
Abhranil Das

Reputation: 5918

You are right about the error. So you have to check if the key is present. 'key' in dict returns True if 'key' is found in dict, otherwise False. Implementing this, here's your full code (with the debugging print statements removed):

raw = "[email protected]:Full Name:shortname\[email protected]:Another Full Name:anothershortname\[email protected]:Foo:bar"
newlines = raw.split("\n")
merged = {}
for message in newlines:
    message = message.split(":")
    if message[0] in merged:
        merged[message[0]].append([message[1], message[2]])
    else:
        merged[message[0]]=[[message[1], message[2]]]    
print merged

Notice the extra brackets for the nested list on the second last line.

Upvotes: 0

DhruvPathak
DhruvPathak

Reputation: 43235

Just check for presence of key, if it is not present, create the key, if it is present, then append the data to existing list.

if(messsage[0] in merged):
     merged[message[0]] = [message[1],[message[2]]
else:
     merged[message[0]].append([[message[1], message[2]])

Upvotes: 0

Niall Byrne
Niall Byrne

Reputation: 2460

May work as:

for message in newlines:
    message = message.split(":")
    temp = []
    temp.append(message[1])
    temp.append(message[2])
    merged[message[0]] = temp

Actually maybe:

for message in newlines:
    message = message.split(":")
    temp = []
    temp.append(message[1])
    temp.append(message[2])
    if message[0] not in merged:
        merged[message[0]] = []
    merged[message[0]].append(temp)

Upvotes: 1

Related Questions