programming -

Python List 的两种排序

Posted on October 9, 2021 |

# import a groupby() method # from itertools module from itertools import groupby # dictionary INFO = [ {'employee': 'XYZ_1', 'company': 'ABC_1'}, {'employee': 'XYZ_2', 'company': 'ABC_2'}, {'employee': 'XYZ_3', 'company': 'ABC_3'}, {'employee': 'XYZ_4', 'company': 'ABC_3'}, {'employee': 'XYZ_5', 'company': 'ABC_2'}, {'employee': 'XYZ_6', 'company': 'ABC_3'}, {'employee': 'XYZ_7', 'company': 'ABC_1'}, {'employee': 'XYZ_8', 'company': 'ABC_2'}, {'employee': 'XYZ_9', 'company': 'ABC_1'} ] # define a fuction for key def key_func(k): return k['company'] # sort INFO data by 'company' key. [Read More]

programming Python

Python3 中的四舍五入

Posted on October 9, 2021 |

最近在项目中遇到前后端计算数值不一样的情况，发现是由于 Python3 数学运算处理方式和 PHP BC Math 不一样 PHP 的 round 函数 round ( float $val , int $precision = 0 , int $mode = PHP_ROUND_HALF_UP ) : float Constants Description PHP_ROUND_HALF_UP Rounds num away from zero when it is half way there, making 1.5 into 2 and -1.5 into -2. PHP_ROUND_HALF_DOWN Rounds num towards zero when it is half way there,making 1. [Read More]

programming Python

算法比较

Posted on October 9, 2021 |

计算 1+2+3+……+100 结果的程序

int i, sum = 0, n = 100;
for (i = 1; i <= n; i++) {
    sum = sum + i;
}
printf("%d", sum);

高斯

int sum = 0, n = 100;
sum = (1 + n) * n/2;
printf("%d", sum);

programming math

Go vs PHP Syntax Comparison

Posted on October 9, 2021 |

Data types PHP types: bool string int //Integer float array object NULL resource Go types: string bool int int8 int16 int32 int64 uint uint8 uint16 uint32 uint64 uintptr byte //uint8 rune //int32 float32 float64 complex64 complex128 array slices map struct Variables Variable declarations Go PHP var i int $i = 0 // integer var f float64 $f = 0.0 // float var b bool $b = false // boolean var s string $s = "" // string var a [2]string $a = [] // array Short variable declarations [Read More]

programming PHP Go

软件应该具备的能力

Posted on October 9, 2021 |

安全一个软件无论是服务端、客户端又或传输过程中安全无法保障无异于把客户、用户的信息泄露，服务端更甚于泄露所有客户、用户的所有信息。

稳定没有客户、用户接受使用经常宕机的服务。

速度快 客户、用户不会花更长时间等待软件的响应，更有电商对此印证

programming

Laravel 使用联合主键

Posted on October 9, 2021 |

在 Model 中表示方式

protected $primaryKey = ['key_one', 'key_two'];
public $incrementing = false;

programming

PHP 不用函数翻转字符串

Posted on October 9, 2021 |

$str = 'hello';

$newstr = '';

$i = 0;

while (!empty($str[$i])) {
	$newstr = $str[$i].$newstr;

	$i++;
}

echo $newstr;

programming PHP

How to Avoid Floating Point Math Error in PHP and Python

Posted on October 7, 2021 |

php -r "var_dump(intval(0.58 * 100));”

int(57)

python3

>>>print(0.58*100)57.99999999999999

other languages http://0.30000000000000004.com

how did this happen http://www.laruence.com/2013/03/26/2884.html

Mathematical extensions in php and decimal module in python to avoid this

php -r "var_dump(intval(bcmul('0.58', '100')));"

int(58)

>>> from decimal import Decimal

>>> from decimal import getcontext

>>> print(Decimal('0.58') * Decimal('100'))

58.00

programming PHP Python