Python Append Key

Building a dict and ordering it into groups by key is sometimes very useful.

Teh following code show using the if .. in option and defaultdict option of checkign for a key when loading the dictionary. Although people warn that using has_key or if .. in type checks slows it down a lot my timings was fairly similar. I left some commented code in for my own reference.

source

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from collections import defaultdict
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from time import time
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sample_size = 10000000
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dct1 = defaultdict(list)
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dct1 = {}
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st_time = time()
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for i in range(1, sample_size):
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    s = str(i)
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    key = s[0:1]
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    name = 'server' + s
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    dct1.setdefault(key, []).append({'name':name,'status':'RUNNING'})  # returns None!
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print (f"\ndct1 defaultdict option: {time() - st_time}")
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#print (dct1)
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# get one key
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#one_key = dct1.get('2')
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#print (one_key)
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#for v in one_key:
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#  print (v)
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# print by key
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#for k,v in dct1.items():
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#  print("\nkey == {}".format(k))
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#  print (v)
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#  #for i in v:
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#  #  print("  {} {}".format(i["name"], i["status"]))
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dct2 = {}
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st_time = time()
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for i in range(1, sample_size):
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    s = str(i)
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    key = s[0:1]
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    name = 'server' + s
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    if key in dct2:
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      dct2[key].append({'name':name,'status': 'STOPPED'})
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    else:
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      dct2.update({key: [{'name': name,'status': 'STOPPED'}]})
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print (f"\ndct2 if .. in option: {time() - st_time}")
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#print (dct2)
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#one_key = dct1.get('1')
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#print (one_key)
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#for v in one_key:
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#  print (v)
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# print by key
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#for k,v in dct2.items():
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#  print("\nkey == {}".format(k))
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#  print (v)
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#  #for i in v:
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#  #  print("  {} {}".format(i["name"], i["status"]))

test

py-assoc-arr$ python3 py-keyed-dict-timing.py

dct1 defaultdict option: 6.392352342605591

dct2 if .. in option: 6.472132921218872