Order of keys in a different Python dict()
Tag : python , By : Sandeep Arneja
Date : March 29 2020, 07:55 AM
I wish this helpful for you , You cannot rely on the key order at all: >>> {1: None, 9: None}
{1: None, 9: None}
>>> {9: None, 1: None}
{9: None, 1: None}
>>> {1: None, 2: None}
{1: None, 2: None}
>>> {2: None, 1: None}
{1: None, 2: None}
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Python is 'key in dict' different/faster than 'key in dict.keys()'
Tag : python , By : user121350
Date : March 29 2020, 07:55 AM
will help you Short answer: In python 2: your assumption is correct: dict.keys() slows down. In python 3: your assumption is not correct: in dict.keys() performs like like in dict #! /usr/bin/python2.7
import datetime as dt
import random
dict_size = 1000000
num_iterations = 100
d = {i: i for i in xrange(dict_size)}
def f():
k = random.randint(0,dict_size-1)
return (k in d)
def g():
k = random.randint(0,dict_size-1)
return (k in d.keys())
def test(func):
t = dt.datetime.utcnow()
for i in xrange(num_iterations):
func()
print "%s --> %1.6f s" % (func, (dt.datetime.utcnow()-t).total_seconds())
test(f)
test(g)
<function f at 0x7ff2e0126d70> --> 0.000598 s
<function g at 0x7ff2e0126de8> --> 5.191553 s
<function f at 0x7f94cb5e6d70> --> 3.614162 s
<function g at 0x7f94cb5e6de8> --> 7.007922 s
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Iterate over a column containing keys from a dict. Return matched keys from second dict keeping order of keys from first
Tag : python , By : Chris Tattum
Date : March 29 2020, 07:55 AM
hop of those help? As I see, you imported OrderedDict, but didn't use it. You should build OrderedDict to save keys order: dict_a = OrderedDict((rows[1],rows[2]) for rows in reader)
dict_b = dict((rows[3],rows[4]) for rows in reader)
for key, value in dict_a.iteritems():
if dict_b[key] == value:
print value
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Why is the order of python dict keys not consistent?
Tag : python , By : Arun Thakkar
Date : March 29 2020, 07:55 AM
wish helps you This behavior is detailed in object.__hash__()'s specification; it's to prevent certain types of malicious input from breaking applications:
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Need help iterating through Python dict keys/values and INSERTing into SQL DB
Tag : python , By : user150694
Date : March 29 2020, 07:55 AM
To fix the issue you can do Consider unpacking your collection of dictionaries into key/value tuples and then parameterize the values tuple in the loop. Assuming the below data structure (list of dictionaries): scale_data_json["operations"] = [{'BMI': 0, 'BodyFat': 10,
'Entrytimestamp': '2018-01-21T19:37:47.821Z',
'MuscleMass': 50, 'OperationType': 'create',
'ServerTimestamp':'2018-01-21T19:37:47.821Z',
'Source':'bluetooth scale',
'Water':37, 'Weight':21},
{'BMI': 0, 'BodyFat': 10,
'Entrytimestamp': '2018-01-21T19:37:47.821Z',
'MuscleMass': 50, 'OperationType': 'create',
'ServerTimestamp':'2018-01-21T19:37:47.821Z',
'Source':'bluetooth scale',
'Water':37, 'Weight':21},
...]
# PREPARED STATEMENT
sql = """INSERT INTO BodyComposition (BMI, BodyFat, Entrytimestamp,
MuscleMass, OperationType, ServerTimestamp,
Source, Water, Weight)
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
"""
# LOOP, UNPACK, BIND PARAMS
for entry in scale_data_json["operations"]:
keys, values = zip(*entry.items())
cursor.execute(sql, values)
cnxn.commit()
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