大约有 40,000 项符合查询结果（耗时：0.0302秒） [XML]
MD5 algorithm in Objective-C
...ons.h"
#import <CommonCrypto/CommonDigest.h> // Need to import for CC_MD5 access
@implementation NSString (MyAdditions)
- (NSString *)md5
{
const char *cStr = [self UTF8String];
unsigned char result[CC_MD5_DIGEST_LENGTH];
CC_MD5( cStr, (int)strlen(cStr), result ); // This is the m...
Why can't (or doesn't) the compiler optimize a predictable addition loop into a multiplication?
...
It does now -- at least, clang does:
long long add_100k_signed(int *data, int arraySize)
{
long long sum = 0;
for (int c = 0; c < arraySize; ++c)
if (data[c] >= 128)
for (int i = 0; i < 100000; ++i)
sum += data[c];
re...
Creating a dynamic choice field
...passing the user to the form init
class waypointForm(forms.Form):
def __init__(self, user, *args, **kwargs):
super(waypointForm, self).__init__(*args, **kwargs)
self.fields['waypoints'] = forms.ChoiceField(
choices=[(o.id, str(o)) for o in Waypoint.objects.filter(use...
ZSH complains about RVM __rvm_cleanse_variables: function definition file not found
...
searched for "whats 'zcompdump' for" while diagnosing the __rvm_cleanse_variables issue... two birds, one search. +1's to everyone.
– max
Mar 21 '15 at 18:54
...
Auto layout constraints issue on iOS7 in UITableViewCell
...n the cell is reused like this:
For Static UITableViewController:
#ifdef __IPHONE_OS_VERSION_MIN_REQUIRED
#if __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_8_0
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [sup...
What's the difference between utf8_general_ci and utf8_unicode_ci?
Between utf8_general_ci and utf8_unicode_ci , are there any differences in terms of performance?
8 Answers
...
MongoDB sort排序、index索引教程 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...排列。
语法
sort()方法基本语法如下所示：
>db.COLLECTION_NAME.find().sort({KEY:1})
注意：
即使键值写错了（即文档中没有该键值），命令本身不会报错，当然排序也没有效果。
实例
col 集合中的数据如下：
{ "_id" : ObjectId("56066542...
Get IP address of visitors using Flask for Python
...est object and then get from this same Request object, the attribute remote_addr.
Code example
from flask import request
from flask import jsonify
@app.route("/get_my_ip", methods=["GET"])
def get_my_ip():
return jsonify({'ip': request.remote_addr}), 200
For more information see the Werkzeu...
Is there a foreach loop in Go?
...
https://golang.org/ref/spec#For_range
A "for" statement with a "range" clause iterates through all entries
of an array, slice, string or map, or values received on a channel.
For each entry it assigns iteration values to corresponding iteration
v...
What do *args and **kwargs mean? [duplicate]
...ments, no matter how many you supply, you could write it like this:
def my_sum(*args):
return sum(args)
It’s probably more commonly used in object-oriented programming, when you’re overriding a function, and want to call the original function with whatever arguments the user passes in.
Y...