flags

Is using an integer flag and bitwise operations an effective way of reducing the memory footprint of high volume Objects? Memory Footprint It is my understanding that commonly a boolean is stored as an int in a JVM implementation. Is this correct? In which case surely the 32 flags represent a large memory footprint reduction. Although of course the JVM implementations vary, so this may not always be the case. Performance It is my understanding that CPUs are very number driven and bitwise operations are about as efficient as things come in computing. Is there a performance penalty - or even

I'm not very used to programming with flags, but I think I just found a situation where they'd be useful: I've got a couple of objects that register themselves as listeners to certain events. What events they register for is dependent on a variable that is sent to them when they are constructed. I think a nice way to do this would be to send bitwise OR connected variables, like such: TAKES_DAMAGE | GRABBABLE | LIQUID, etc. Then, in the constructor, the object can check what flags are set and register it self as listener for the ones that are. But this is where I get confused. Preferably, the

I'm implementing GCM. My app has two activities, say A and B . I'm using this code to launch B from the NotificationBar: long when = System.currentTimeMillis(); NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE); String title = context.getString(R.string.app_name); Notification notification = new Notification(R.drawable.app_notification_icon, "De Centrale", when);//message Intent notificationIntent = new Intent(context, B.class); notificationIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP); //

type Comment struct { name string // 该指针为空, 初始化时才能设置为空; flags *FlagSet PostRun func(cmd *Comment, args []string) //结构中的抽象方法 } c := &Comment{"name",nil, func(cmd *Comment, args []string) { strings.Join(args," ") }} func (c *Comment) Flag() *FlagSet{ if c.flags == nil{ c.flags = NewFlagSet(c.name, ContinueOnError) } return c.flags }

https://www.jianshu.com/p/55cbd3753ee8 文章来源: https://www.cnblogs.com/kkwy/p/11245148.html

set $eflags does not change eflags value. The old eflags value remains after eg. =>$set $eflag=0x243 [this is just an example input]. Alternatively, is there any way to set individual flags of eflags ? I'm looking for something like: set ZF[zero flag] . Is there a gdb command to do that? Ciro Santilli 新疆改造中心法轮功六四事件 set $eflags without parenthesis works in GDB 7.7.1 To set an individual flag, use its index. E.g., ZF is the 6th bit, so we can set it with: set $ZF = 6 # define a GDB variable: no effect on registers set $eflags |= (1 << $ZF) # set bit 6 in EFLAGS, the ZF bit. The same goes for all

I need to emulate enum type in Javascript and approach seems pretty straight forward: var MyEnum = {Left = 1; Right = 2; Top = 4; Bottom = 8} Now, in C# I could combine those values like this: MyEnum left_right = MyEnum.Left | MyEnum.Right and then I can test if enum has certain value: if (left_right & MyEnum.Left == MyEnum.Left) {...} Can I do something like that in Javascript? In javascript you should be able to combine them as: var left_right = MyEnum.Left | MyEnum.Right; Then testing would be exactly as it is in your example of if ( (left_right & MyEnum.Left) == MyEnum.Left) {...} CMS You

I find out that we can use cool flags that scroll both toolbar and even content by using layout_scrollFlags . In my case, I have a layout like this: <android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent"> <android.support.design.widget.AppBarLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"> <android.support.v7.widget.Toolbar

I have a column of timedelta in pandas. It is in the format x days 00:00:00. I want to filter out and flag the rows which have a value >=30 minutes. I have no clue how to do that using pandas. I tried booleans and if statements but it didn't work. Any help would be appreciated. You can convert timedelta s to seconds by total_seconds and compare with scalar: df = df[df['col'].dt.total_seconds() < 30] Or compare with Timedelta : df = df[df['col'] < pd.Timedelta(30, unit='s')] Sample : df = pd.DataFrame({'col':pd.to_timedelta(['25:10:01','00:01:20','00:00:20'])}) print (df) col 0 1 days 01:10:01

python 的re库为： raw string 类型（原生字符串类型，即不含转义字符） 在字符串前面加 r'...'就行了 Re库主要功能函数 re.rearch(pattern,string,flags=0) 　　在一个字符串中搜索匹配表达式第一个位置，返回match对象 　　*pattern:正则表达式的字符串或原生字符串表示 　　*string：待匹配字符串 　　*flags：控制标记 　　　　常用标记： 　　　　　　re.I re.IGNORECASE #忽略表达式的大小写，[A-Z]能够匹配小写[a-z] 　　　　　　re.M re.MULTILINE #表达式中的^操作符，从每行的开始进行匹配 　　　　　　re.S re.DOTALL #表达式中的 . 点操作符，能够匹配所以字符，默认匹配除换行外的所有字符串 re.match(pattern,string,flags=0) 　　从一个字符串的 开始 位置匹配，返回match对象 re.findall(pattern,string,flags=0) 　　以列表类型返回全部匹配 re.split(pattern,string,maxsplit=0,flags=0) 　　将一个字符串安装表达式匹配结果进行分割，返回列表类型 　　*maxsplit约定分割成几段 re.finditer(pattern,string