integer

问题 In book Algorithms fourth edition by Robert Sedgewick on page 200, it says "for example, if you have 1GB of memory on your computer (1 billion bytes), you cannot fit more than about 32 million int values." I got confused after my calculation: 1,000,000,000 bytes/4 bytes = 250 million How the author got 32 million? The book describes like below: 回答1: The author has acknowledged that this is an error in this book website, please refer to the link as follows: http://algs4.cs.princeton.edu/errata

问题 We are currently doing some iterations and other operations using x++; where x is an Integer and not an int . Operations may be repeated throughout some user operations on our system but nothing too complex or numerous like a Mathematical application, maximum up to 10000 times per user transaction.. Will this unboxing and later boxing affect our performance by some noticeable milliseconds ? 回答1: http://download.oracle.com/javase/1.5.0/docs/guide/language/autoboxing.html "The performance of

问题 We are currently doing some iterations and other operations using x++; where x is an Integer and not an int . Operations may be repeated throughout some user operations on our system but nothing too complex or numerous like a Mathematical application, maximum up to 10000 times per user transaction.. Will this unboxing and later boxing affect our performance by some noticeable milliseconds ? 回答1: http://download.oracle.com/javase/1.5.0/docs/guide/language/autoboxing.html "The performance of

问题 While doing some random experimentation with a factorial program in C, Python and Scheme. I came across this fact: In C, using 'unsigned long long' data type, the largest factorial I can print is of 65. which is '9223372036854775808' that is 19 digits as specified here. In Python, I can find the factorial of a number as large as 999 which consists of a large number of digits, much more than 19. How does CPython achieve this? Does it use a data type like 'octaword' ? I might be missing some

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 6 years ago . Given a range of integers, how do I generate a random integer divisible by 5 in that range? I'm using Java 回答1: just generate a regular random integer and multiply it by 5! details: generate a random integer in [0, n) where n is the number of multiples of 5 in your range, then multiply it by 5 and add the lowest

问题 I would like to know if there is a simple way to turn [5,2,10] into "52a" . Where its not just to this case, I want to associate any number >9 with the corresponding letter. Thanks in advance. 回答1: You want to do something to each element of a list in order to get a new list. In other words, you want to apply a function (that you will have to define yourself) to each element. This is what the map function from the Prelude is for. To convert between integers and individual characters, you

问题 For a specific need I am building a four byte integer out of four one byte chars, using nothing too special (on my little endian platform): return (( v1 << 24) | (v2 << 16) | (v3 << 8) | v4); I am aware that an integer stored in a big endian machine would look like AB BC CD DE instead of DE CD BC AB of little endianness, although would it affect the my operation completely in that I will be shifting incorrectly, or will it just cause a correct result that is stored in reverse and needs to be

问题 When using integer values in my own code, I always try to consider the signedness, asking myself if the integer should be signed or unsigned. When I'm sure the value will never need to be negative, I then use an unsigned integer. And I have to say this happen most of the time. When reading other peoples' code, I rarely see unsigned integers, even if the represented value can't be negative. So I asked myself: «is there a good reason for this, or do people just use signed integers because the

问题 When using integer values in my own code, I always try to consider the signedness, asking myself if the integer should be signed or unsigned. When I'm sure the value will never need to be negative, I then use an unsigned integer. And I have to say this happen most of the time. When reading other peoples' code, I rarely see unsigned integers, even if the represented value can't be negative. So I asked myself: «is there a good reason for this, or do people just use signed integers because the

问题 This is what I have, currently. Is there any nicer way to do this? import struct def int32_to_uint32(i): return struct.unpack_from("I", struct.pack("i", i))[0] 回答1: Not sure if it's "nicer" or not... import ctypes def int32_to_uint32(i): return ctypes.c_uint32(i).value 回答2: using numpy for example: import numpy result = numpy.uint32( numpy.int32(myval) ) or even on arrays, arr = numpy.array(range(10)) result = numpy.uint32( numpy.int32(arr) ) 来源： https://stackoverflow.com/questions/16452232