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, programmers are even allowed to construct NaN values with special locating modes (through the Float. intBitsToFloat () method ). For example, programmers can use this customized special location mode in NaN values to express some diagnostic information.Like NaN, the infinite exponent portion of the special value is also 128, but the infinite ending number must all be 0. Infinity is used to express the Overflow problem in computing. For example, when

ECMAScript have values equivalent to these two Boolean values. To convert a value to its corresponding Boolean value, you can call the Transform function Boolean (), for example:var str1= "HI";var strboolean=boolean (STR1);Console.log (Strboolean);//trueYou can call the Boolean () function on a value of any data type, and always return a Boolean value.Various data types and their corresponding conversion rules: Data type The value converted to true Value converted to F

, after the decimal point contains at least one digitvar floatnum=1. -----There is no number after the decimal point, it is resolved to 1var floatnum=11.0------Integer, resolved to 11For large and very small values can be represented by the expression of the floating point in the E-notation, the value of e is equal to the value in front of e multiplied by the exponential power of 10B: The value range, ECMAScript can be represented by the smallest value saved in Number.min_value, in most of the b

1. Using "Use strict" on the top of the script or in the first line of the function will enable strict mode or execute in strict mode2. Define the variable that holds the object and initialize it to null3.null = = Underfined,is true;4.typeof Null,is object;5.typeof is operator, not operand6. When calculating, octal number (starting with 0, if written as 079, then decimal 79), and hexadecimal number (0x), will be converted to decimal7.0.1 + 0.2 = = 0.3,is false; Do not test a specific floating-po

interpreted as hexadecimal numbers.Instancevar y = 0377;var z = 0xFF;Never write 0 in front of the number unless you need to make an octal conversion.By default, JavaScript numbers are displayed in decimal.But you can use the ToString () method to output 16 binary, 8 binary, and 2 binary.Instancevar mynumber=128;Mynumber.tostring (16); Returns 80Mynumber.tostring (8); Returns 200Mynumber.tostring (2); Returns 10000000Infinity (Infinity)When the resul

simultaneously3. Output logs to both file and screen at the same timeImport Logginglogging.basicconfig ( level=logging. DEBUG, Format='% (asctime) s% (filename) s[line:% (lineno) d]% (levelname) s% (message) s', Datefmt='%a,%d%b%Y%h:%m:%s', filename='Myapp.log', FileMode='W') ################################################################################################# #定义一个StreamHandler , print info-level or higher log information to a standard error and add it to the current log processing

and filename are specified simultaneously3. Output logs to both file and screen at the same time Import loggingLogging.basicconfig (level=logging. DEBUG,format= '% (asctime) s% (filename) s[line:% (lineno) d]% (levelname) s% (message) s ',Datefmt= '%a,%d%b%Y%h:%m:%s ',Filename= ' Myapp.log ',Filemode= ' W ')##################################################################################################定义一个StreamHandler, print Info-level or higher log information to a standard err

/* * @FileName: TEST_SLEEP.C * @Author: WZJ * @Brief: * * * @History: * * @Date: February 07, 2012 Tuesday 22:20:00 * */ #include #include #include #include #include #include #include #include #include int main (int argc, char **argv) { unsigned int ntimetestsec = 0; unsigned int ntimetest = 0; struct Timeval tvbegin; struct Timeval tvnow; int ret = 0; unsigned int ndelay = 0; struct Timeval TV; int fd = 1; int i

and filename are specified simultaneously3. Output logs to both file and screen at the same time Import loggingLogging.basicconfig (level=logging. DEBUG,format= '% (asctime) s% (filename) s[line:% (lineno) d]% (levelname) s% (message) s ',Datefmt= '%a,%d%b%Y%h:%m:%s ',Filename= ' Myapp.log ',Filemode= ' W ')##################################################################################################定义一个StreamHandler, print Info-level or higher log information to a standard err

of the log, which specifies the output to the Sys.stderr,sys.stdout or file, the default output to Sys.stderr, and the stream is ignored 3 when the stream and filename are specified at the same time . Output logs to files and screens at the same time Import loggingLogging.basicconfig (level=logging. DEBUG,format= '% (asctime) s% (filename) s[line:% (lineno) d]% (levelname) s% (message) s ',Datefmt= '%a,%d%b%Y%h:%m:%s ',Filename= ' Myapp.log ',Filemode= ' W ')########################

: Specifies the output stream of the log, which specifies the output to the Sys.stderr,sys.stdout or file, the default output to Sys.stderr, and the stream is ignored 3 when the stream and filename are specified at the same time . Output logs to files and screens at the same time Import loggingLogging.basicconfig (level=logging. DEBUG,format= '% (asctime) s% (filename) s[line:% (lineno) d]% (levelname) s% (message) s ',Datefmt= '%a,%d%b%Y%h:%m:%s ',Filename= ' Myapp.log ',Filemode= '

, ovalue); (2)value2.it_value.tv_sec = 0;Value2.it_value.tv_usec = 500000;value2.it_interval.tv_sec = 0;Value2.it_interval.tv_usec = 500000;Setitimer (Itimer_virtual, value2, ovalue);for (;;);}Setitimer does not cause the thread to block or cause the thread to switch, it is simple to start a timer, start timing, and this timing should be based on the kernel, (Windwos SetTimer is based on a message model) Setitimer Although there are three types itimer_real,itimer_virtual itimer_prof, but at the