integer

问题 I'm working on a data validator package for PHP (mostly as an exercise in some of the new additions in 5.3 such as namespaces). I'm planning to have a main validator class which uses plugin classes to do the actual validation. The first validation plugin I'm building is just a simple one for integers. The source is below: namespace validator\validatorplugins; class Integer implements ValidatorPlugin { private $field = NULL; public function cast () { return ($this -> field = (int) ($this ->

问题 I'm using Doctrine 2 for my DB and I'm currently trying to set a length for one of my column that has an "integer" type but it just doesn't seem to be taken. /** @Column(type="integer", length=255) */ protected $number; When I check my database it still says "int(11)" instead of "int(255)". I haven't found anyone experiencing that problem on google or maybe my keywords ain't working so good. I've seen a few example of people using length=XXX and not complaining about it so I thought it would

问题 In my bash script, I set-up the following operations year=0050 echo $(printf %04d $year) >0040 I do not understand why 0040 is returned instead of 0050. I eventually found that to get the system to print 0050 correctly, I will have to do this instead. year=50 echo $(printf %04d $year) >0050 Are there any insights as to why the first case happens? 回答1: It's because numbers with a leading zero are interpreted as octal by Bash, and octal 50 is decimal 40. To fix it, you can either strip the

问题 x = [1, 2, 3, ... ] y = sum(x) The sum of x is 2165496761, which is larger than the limit of 32bit integer So sum(x) returns -2129470535. How can I get the correct value by converting it to long integer? Here is my import list: import math, csv, sys, re, time, datetime, pickle, os, gzip from numpy import * 回答1: The reason why you get this invalid value is that you're using np.sum on a int32 . Nothing prevents you from not using a np.int32 but a np.int64 or np.int128 dtype to represent your

问题 In C, C++, and Java, an integer has a certain range. One thing I realized in Python is that I can calculate really large integers such as pow(2, 100) . The same equivalent code, in C, pow(2, 100) would clearly cause an overflow since in 32-bit architecture, the unsigned integer type ranges from 0 to 2^32-1. How is it possible for Python to calculate these large numbers? 回答1: Basically, big numbers in Python are stored in arrays of 'digits'. That's quoted, right, because each 'digit' could

问题 I needed to convert a fractional part of a number into integer without a comma, for example I have 3.35 I want to get just 35 part without zero or a comma, Because I used the modf() function to extract the the fractional part but it gives me a 0.35 if there is any way to do that or to filter the '0.' part I will be very grateful if you show me how with the smaller code possible, 回答1: A bit more efficient than converting to a string and back again: int fractional_part_as_int(double number, int

问题 I needed to convert a fractional part of a number into integer without a comma, for example I have 3.35 I want to get just 35 part without zero or a comma, Because I used the modf() function to extract the the fractional part but it gives me a 0.35 if there is any way to do that or to filter the '0.' part I will be very grateful if you show me how with the smaller code possible, 回答1: A bit more efficient than converting to a string and back again: int fractional_part_as_int(double number, int

问题 I'm using MATLAB R2016a genetic algorithm optimization toolbox to optimize 80 integer values. I have these constraints: x(80) > x(79) > x(78) > x(77) > x(76) ... x(5) > x(4) > x(3) > x(2) > x(1) The range for all integer variables is between 1 and 500. I used this code in MATLAB: f = @(x)Cost_function(x, my_data); num_of_var = 80; for mx = 1:num_of_var-1 A(mx,:) = [zeros(1,mx-1),1,-1, zeros(1,num_of_var-mx-1)]; end b = repmat(-3, [num_of_var-1,1]); lb = ones([num_of_var-1,1]); up = repmat(500

问题 Given an integer value, I need some way to find out the minimum number of bytes needed to store the value. The value may be signed or unsigned, up to 64-bit . Also take the sign bit into account for signed integers. For example: 8 requires 1 byte at minimum unsigned 255 requires 1 byte at minimum signed 255 requires 2 bytes at minimum 4351 requires 2 bytes at minimum -4294967296 requires 5 bytes at minimum unsigned 0xFFFFFFFFFFFFFFFF requires 8 bytes at minimum I can think of a quick-and

问题 This question already has answers here : Catch and compute overflow during multiplication of two large integers (12 answers) Closed 5 months ago . In close to the metal languages like C, C++ and D, what's the most efficient reasonably portable way (i.e. w/o using assembler, though you may assume two's complement arithmetic and wrap-around behavior) to detect overflow of an unsigned 64-bit integer on multiplication? 回答1: You can detect overflow in advance by dividing the maximum value