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What __init__ and self do on Python?
...iable declared inside an __init__ function:
class MyClass(object):
i = 123
def __init__(self):
self.i = 345
a = MyClass()
print(a.i)
print(MyClass.i)
Output:
345
123
share
|
...
mysql error 1364 Field doesn't have a default values
...ERO,NO_AUTO_CREATE_USER,NO_ENGINE_UBSTITUTION'
– waza123
Oct 30 '17 at 17:55
...
Understanding :source option of has_one/has_many through of Rails
...'ve chosen to namespace the Dog::Breed, because we want to access Dog.find(123).breeds as a nice and convenient association.
Now, if we now want to create a has_many :dog_breeds, :through => :dogs association on Pet, we suddenly have a problem. Rails won't be able to find a :dog_breeds associati...
Convert Rows to columns using 'Pivot' in SQL Server
..., 212),
(105, 2, 78),
(109, 2, 97),
(105, 3, 60),
(102, 3, 123),
(101, 3, 220),
(109, 3, 87);
If your values are known, then you will hard-code the query:
select *
from
(
select store, week, xCount
from yt
) src
pivot
(
sum(xcount)
for week in ([1], [2], [3])
) pi...
Are HTTP headers case-sensitive?
In a blog post I use the following PHP to set the content-type of a response:
8 Answers
...
通过 ulimit 改善系统性能 - 操作系统(内核) - 清泛网 - 专注C/C++及内核技术
...资源的条件下保证程序的运作，ulimit 是我们在处理这些问题时，经常使用的一种简单手段。ulimit 是一种 linux 系统的内键功能，它具有一套参数集，用于为由它生成的 shell 进程及其子进程的资源使用设置限制。本文将在后面的...
Javascript foreach loop on associative array object
...ceving, can you explain more on why not use var in loops? I come from C++/PHP background and I don't understand this. scoping does exist in the loop, but temporary, so I am not sure what you mean.
– Dennis
Jul 21 '16 at 21:33
...
Is there any difference between GROUP BY and DISTINCT
...ukas Eder
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...
Go > operators
...y Arithmetic operators and its the same in other languages here is a basic PHP , C , Go Example
GO
package main
import (
"fmt"
)
func main() {
var t , i uint
t , i = 1 , 1
for i = 1 ; i < 10 ; i++ {
fmt.Printf("%d << %d = %d \n", t , i , t<<i)
}
...
How to convert a string to lower case in Bash?
...uby`
Or Perl (probably my favorite):
b=`perl -e "print lc('$a');"`
Or PHP:
b=`php -r "print strtolower('$a');"`
Or Awk:
b=`echo "$a" | awk '{ print tolower($1) }'`
Or Sed:
b=`echo "$a" | sed 's/./\L&/g'`
Or Bash 4:
b=${a,,}
Or NodeJS if you have it (and are a bit nuts...):
b=`e...