大约有 48,000 项符合查询结果（耗时：0.0178秒） [XML]
Remove element by id
... children. HTML is a superset of XML (sort of).
– Hal50000
Nov 2 '16 at 1:30
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What does “Splats” mean in the CoffeeScript tutorial?
...args, as it allows you to treat function parameters as list
for example:
concat = (args...) -> args.join(', ')
concat('hello', 'world') == 'hello, world'
concat('ready', 'set', 'go!') == 'ready, set, go!'
it works in assginments, too:
[first, rest...] = [1, 2, 3, 4]
first == 1
rest == [2, 3,...
How can you sort an array without mutating the original array?
... this is really great.i think easier to understand than the concat and other approaches
– sktguha
Aug 31 at 20:02
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String is immutable. What exactly is the meaning? [duplicate]
... string "knowledge"
Lets see how the below statement works:
str = str.concat(" base");
This appends a string " base" to str. But wait, how is this possible, since String objects are immutable? Well to your surprise, it is.
When the above statement is executed, the VM takes the value of Strin...
Remove all values within one list from another list? [duplicate]
....
Experiments were done using pythonbenchmark tool and with
a = range(1,50000) # Source list
b = range(1,15000) # Items to remove
Results:
def comprehension(a, b):
return [x for x in a if x not in b]
5 tries, average time 12.8 sec
def filter_function(a, b):
return filter(lambda x:...
Swapping column values in MySQL
...-+
3 rows in set (0.00 sec)
mysql> update swapper set
-> foo = concat(foo, "###", bar),
-> bar = replace(foo, concat("###", bar), ""),
-> foo = replace(foo, concat(bar, "###"), "");
Query OK, 3 rows affected (0.00 sec)
Rows matched: 3 Changed: 3 Warnings: 0
mysql> se...
How do I add the contents of an iterable to a set?
...python3
from timeit import Timer
a = set(range(1, 100000))
b = list(range(50000, 150000))
def one_by_one(s, l):
for i in l:
s.add(i)
def cast_to_list_and_back(s, l):
s = set(list(s) + l)
def update_set(s,l):
s.update(l)
results are:
one_by_one 10.184448844986036
cast_...
Add one row to pandas DataFrame
... It is worth noting however, that concat (and therefore append) makes a full copy of the data, and that constantly reusing this function can create a significant performance hit. If you need to use the operation over several datasets, use a list comprehension...
How to write to an existing excel file without overwriting data (using pandas)?
...iteration you append the dataframe to a list. In the end you only need to concat. If they follow the same structure will work as a charm. list_my_dfs = [df1, df2, ...] # List of your dataframes my_dfs_together = pd.concat(list_my_df ) # concat my dataframes in a single df
– ...
SQL Joins Vs SQL Subqueries (Performance)?
...mijoin Transformations
Rewriting Subqueries as Joins
I have a table with 50000 elements, the result i was looking for was 739 elements.
My query at first was this:
SELECT p.id,
p.fixedId,
p.azienda_id,
p.categoria_id,
p.linea,
p.tipo,
p.nome
FROM prodotto p
WHERE p.azien...