arguments

问题 I define the piecewise function def Li(x): return piecewise(x, [x < 0, x >= 0], [lambda t: sin(t), lambda t: cos(t)]) And when I evaluate Li(1.0) The answer is correct Li(1.0)=array(0.5403023058681398) , But if I write Li(1) the answer is array(0) . I don't understand this behaviour. 回答1: It seems that piecewise() converts the return values to the same type as the input so, when an integer is input an integer conversion is performed on the result, which is then returned. Because sine and

问题 I am trying execute my Python script as: python series.py supernatural 4 6 Supernatural : TV Series name 4 : season number 6 : episode number Now in my script I am using the above three arguments to fetch the title of the episode: import tvrage.api import sys a = sys.argv[1] b = sys.argv[2] c = sys.argv[3] temp = tvrage.api.Show(a) name = temp.season(b).episode(c) # Line:19 print ( name.title) But I am getting this error: File "series.py", line 19, in <module>: name = super.season(b).episode

问题 I am trying execute my Python script as: python series.py supernatural 4 6 Supernatural : TV Series name 4 : season number 6 : episode number Now in my script I am using the above three arguments to fetch the title of the episode: import tvrage.api import sys a = sys.argv[1] b = sys.argv[2] c = sys.argv[3] temp = tvrage.api.Show(a) name = temp.season(b).episode(c) # Line:19 print ( name.title) But I am getting this error: File "series.py", line 19, in <module>: name = super.season(b).episode

问题 From Here it seems that default argument are not supported by C. I have the following method in exported library: extern "C" { __declspec (dllexport) uintptr_t Method(int freq, int *pRetval, bool *support2MHz); } If i made last argument optional like this: extern "C" { __declspec (dllexport) uintptr_t Method(int freq, int *pRetval, bool *support2MHz = NULL); } My dll is still compiled. My question is why? Everyone says the default arguments are not supported in C code. I use C++ for MS 2015.

问题 From Here it seems that default argument are not supported by C. I have the following method in exported library: extern "C" { __declspec (dllexport) uintptr_t Method(int freq, int *pRetval, bool *support2MHz); } If i made last argument optional like this: extern "C" { __declspec (dllexport) uintptr_t Method(int freq, int *pRetval, bool *support2MHz = NULL); } My dll is still compiled. My question is why? Everyone says the default arguments are not supported in C code. I use C++ for MS 2015.

问题 Let consider a typical deparse(substitute( R call: f1 <-function(u,x,y) {print(deparse(substitute(x)))} varU='vu' varX='vx' varY='vy' f1(u=varU,x=varX,y=varY) That results in [1] "varX" which is what we expect and we want. Then, comes the trouble, I try to get a similar behaviour using the ... arguments i.e. f2 <- function(...) { l <- list(...) x=l$x print(deparse(substitute(x))) ### this cannot work but I would like something like that } That, not surprisingly, does not work : f2(u=varU,x

问题 Let consider a typical deparse(substitute( R call: f1 <-function(u,x,y) {print(deparse(substitute(x)))} varU='vu' varX='vx' varY='vy' f1(u=varU,x=varX,y=varY) That results in [1] "varX" which is what we expect and we want. Then, comes the trouble, I try to get a similar behaviour using the ... arguments i.e. f2 <- function(...) { l <- list(...) x=l$x print(deparse(substitute(x))) ### this cannot work but I would like something like that } That, not surprisingly, does not work : f2(u=varU,x

问题 Here is a simple example of using keyword arguments in a function call. Nothing special. def foo(arg1,arg2, **args): print arg1, arg2 print (args) print args['x'] args ={'x':2, 'y':3} foo(1,2,**args) Which prints, as expected: 1 2 {'y': 3, 'x': 2} 2 I am trying to pass the same style keyword arguments to a multiprocessing task, but the use of **, in the args list is a syntax error. I know that my function, stretch() will take two positional arguments and n keyword arguments. pool =

问题 Suppose we have an R function whose arguments must be selected out of a finite set of elements. Like qplot(..., geom="") . And geom can take only some values, like bar or point . How can I find out all the valid values the argument of a given function may take? Apart from docs or Internet, which often miss all possible values. Perhaps, some R function can help? 回答1: If the function of interest is defined like f <- function(a = c("foo","bar")) { match.arg(a) } i.e. when the options are defined

问题 def parse(self, response): for sel in response.xpath('//tbody/tr'): item = HeroItem() item['hclass'] = response.request.url.split("/")[8].split('-')[-1] item['server'] = response.request.url.split('/')[2].split('.')[0] item['hardcore'] = len(response.request.url.split("/")[8].split('-')) == 3 item['seasonal'] = response.request.url.split("/")[6] == 'season' item['rank'] = sel.xpath('td[@class="cell-Rank"]/text()').extract()[0].strip() item['battle_tag'] = sel.xpath('td[@class="cell-BattleTag"