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How to write the Fibonacci Sequence?
...bject every time the function is called, but normally you wouldn't use a mutable default argument for exactly this reason):
def mem_fib(n, _cache={}):
'''efficiently memoized recursive function, returns a Fibonacci number'''
if n in _cache:
return _cache[n]
elif n > 1:
...
Sqlite: CURRENT_TIMESTAMP is in GMT, not the timezone of the machine
I have a sqlite (v3) table with this column definition:
11 Answers
11
...
UPDATE and REPLACE part of a string
I've got a table with two columns, ID and Value . I want to change a part of some strings in the second column.
9 Answer...
LISTAGG in Oracle to return distinct values
...tagg(distinct the_column, ',') within group (order by the_column)
from the_table
18c and earlier:
select listagg(the_column, ',') within group (order by the_column)
from (
select distinct the_column
from the_table
) t
If you need more columns, something like this might be what you are lo...
C# switch statement limitations - why?
...a CIL switch statement which is indeed a constant time branch using a jump table. However, in sparse cases as pointed out by Ivan Hamilton the compiler may generate something else entirely.
This is actually quite easy to verify by writing various C# switch statements, some sparse, some dense, and ...
Bulk insert with SQLAlchemy ORM
...scoped_session(sessionmaker())
engine = None
class Customer(Base):
__tablename__ = "customer"
id = Column(Integer, primary_key=True)
name = Column(String(255))
def init_sqlalchemy(dbname='sqlite:///sqlalchemy.db'):
global engine
engine = create_engine(dbname, echo=False)
...
Restrict varchar() column to specific values?
...t on that column which would restrict values? Something like:
CREATE TABLE SomeTable
(
Id int NOT NULL,
Frequency varchar(200),
CONSTRAINT chk_Frequency CHECK (Frequency IN ('Daily', 'Weekly', 'Monthly', 'Yearly'))
)
...
Split column at delimiter in data frame [duplicate]
... C D
Essentially, it's a fancy convenience wrapper for using read.table(text = some_character_vector, sep = some_sep) and binding that output to the original data.frame. In other words, another A base R approach could be:
df <- data.frame(ID=11:13, FOO=c('a|b','b|c','x|y'))
cbind(df, re...
How to make MySQL handle UTF-8 properly
... query/insert into the database
use DEFAULT CHARSET=utf8 when creating new tables
at this point your MySQL client and server should be in UTF-8 (see my.cnf). remember any languages you use (such as PHP) must be UTF-8 as well. Some versions of PHP will use their own MySQL client library, which may no...
PostgreSQL - max number of parameters in “IN” clause?
... possible if the inputs are all scalars (no RowExprs) and there is a
* suitable array type available. If not, we fall back to a boolean
* condition tree with multiple copies of the lefthand expression.
* Also, any IN-list items that contain Vars are handled as separate
* boolean conditions, bec...