大约有 40,000 项符合查询结果（耗时：0.0455秒） [XML]
How to find list of possible words from a letter matrix [Boggle Solver]
...n Python that I just coded up:
#!/usr/bin/python
class TrieNode:
def __init__(self, parent, value):
self.parent = parent
self.children = [None] * 26
self.isWord = False
if parent is not None:
parent.children[ord(value) - 97] = self
def MakeTrie(dict...
How to get the original value of an attribute in Rails
...
Before rails 5.1
Appending _was to your attribute will give you the previous value.
For rails 5.1+
Copied from Lucas Andrade's answer below: https://stackoverflow.com/a/50973808/9359123
Appending _was is deprecated in rails 5.1, now you should ap...
How do I pass extra arguments to a Python decorator?
... it needs to return another function which is the actual decorator:
def my_decorator(param):
def actual_decorator(func):
print("Decorating function {}, with parameter {}".format(func.__name__, param))
return function_wrapper(func) # assume we defined a wrapper somewhere
ret...
How to convert list of tuples to multiple lists?
...
xs, ys = [x for x, y in zs], [y for x, y in zs]
return xs, ys
if __name__ == '__main__':
from timeit import timeit
setup_string='''\
N = 2000000
xs = list(range(1, N))
ys = list(range(N+1, N*2))
zs = list(zip(xs, ys))
from __main__ import t1, t2, t3
'''
print(f'zip:\t\t{timeit(...
How do JavaScript closures work?
...ing
In the following code, function onClick closes over variable BACKGROUND_COLOR.
const $ = document.querySelector.bind(document)
const BACKGROUND_COLOR = 'rgba(200,200,242,1)'
function onClick() {
$('body').style.background = BACKGROUND_COLOR
}
$('button').addEventListener('click', onClick...
sqlalchemy unique across multiple columns
... declares those in the table definition, or if using declarative as in the __table_args__:
# version1: table definition
mytable = Table('mytable', meta,
# ...
Column('customer_id', Integer, ForeignKey('customers.customer_id')),
Column('location_code', Unicode(10)),
UniqueConstraint...
How does Django's Meta class work?
...n [2]: User.Meta
Out[2]: django.contrib.auth.models.Meta
In [3]: User.Meta.__dict__
Out[3]:
{'__doc__': None,
'__module__': 'django.contrib.auth.models',
'abstract': False,
'verbose_name': <django.utils.functional.__proxy__ at 0x26a6610>,
'verbose_name_plural': <django.utils.functional...
What is the difference between save and insert in Mongo DB?
...is essentially the same.
save behaves differently if it is passed with an "_id" parameter.
For save, If the document contains _id, it will upsert querying the collection on the _id field, If not, it will insert.
If a document does not exist with the specified _id value, the save() method performs a...
Extract traceback info from an exception object
...n you're using.
In Python 3
It's simple: exceptions come equipped with a __traceback__ attribute that contains the traceback. This attribute is also writable, and can be conveniently set using the with_traceback method of exceptions:
raise Exception("foo occurred").with_traceback(tracebackobj)
...
How to len(generator()) [duplicate]
...e advantages over functions that return lists. However, you could len(list_returning_function()) . Is there a way to len(generator_function()) ?
...