conditional

问题 So the operator precedence of the ternary operator in C seems truly bizarre to me. Case in point: #include <stdio.h> int main () { int i=5; int j=6; int k=7; printf("A: %d\n", i+j+(k!=7)?1:11); //prints 1 printf("B: %d\n", i+j+((k!=7)?1:11)); //prints 22 return 0; } This seems similar to the question here: C++ ternary conditional and assignment operator precedence Ternary operator evaluation order As a clarification, I understand that the parentheses make it work, as my comments in my

问题 So the operator precedence of the ternary operator in C seems truly bizarre to me. Case in point: #include <stdio.h> int main () { int i=5; int j=6; int k=7; printf("A: %d\n", i+j+(k!=7)?1:11); //prints 1 printf("B: %d\n", i+j+((k!=7)?1:11)); //prints 22 return 0; } This seems similar to the question here: C++ ternary conditional and assignment operator precedence Ternary operator evaluation order As a clarification, I understand that the parentheses make it work, as my comments in my

问题 I have a vector of randomly sampled numbers. For example, vec1 <- sample(1:574) I would like to assign first 25 percent value in this sampled vector as H and rest elements as L. I have tried using ifelse but that gives values 1 to 143 as H and values greater that 143 as L. But I want first 143 values to have H and rests as L. For elements below, I want first 143th elements (i.e.first 4 rows upto 44) will be H and all rests will be L.That means the first element which values 393 will get H,

问题 Is it possible to make the DirectoryIndex value in a .htaccess file conditional based on IP, so that - for example - my IP see's DirectoryIndex as index.html and everyone else sees DirectoryIndex as index.php? Is there a solution other than mod_rewrite ? 回答1: As far as I know, there is no conditional for DirectoryIndex. You could simulate that with a mod_rewrite directive like this one: RewriteCond %{REMOTE_ADDR} your_ip RewriteCond -d RewriteRule (.*)/$ $1/index.html If you want to exclude

问题 I'm having problems incrementing a counter under certain conditions. Input: <Users> <User> <id>1</id> <username>jack</username> </User> <User> <id>2</id> <username>bob</username> </User> <User> <id>3</id> <username>bob</username> </User> <User> <id>4</id> <username>jack</username> </User> </Users> Wanted Output: <Users> <User> <id>1</id> <username>jack01</username> </User> <User> <id>2</id> <username>bob01</username> </User> <User> <id>3</id> <username>bob02</username> </User> <User> <id>4<

问题 This question differs in that the classic "use a function" answer WILL NOT work. Adding a note to an existing Alias question is equivalent to sending a suggestion e-mail to Yahoo. I am trying to write macros to get around BASH's horrendous IF syntax. You know, the [, [[, ((...BASH: the PHP of flow control...just add another bracket. I'm still waiting for the "(((((((" form. Not quite sure why BASH didn't repurpose "(", as "(" has no real semantics at the if statement. The idea is to have

问题 I am unsure if all of the code will be necessary or not so i will post it: # Tic-Tac-Toe # Plays the game of tic-tac-toe against a human opponent # global constants X = "X" O = "O" EMPTY = " " TIE = "TIE" NUM_SQUARES = 9 def display_instruct(): """Display game instructions.""" print( """ Welcome to the greatest intellectual challenge of all time: Tic-Tac-Toe. This will be a showdown between your human brain and my silicon processor. You will make your move known by entering a number, 0 - 8.

问题 I am trying to build a model that will have slightly different equations based on whether or not certain components exist (in my case, fluid ports). A code like the following will not work: parameter Boolean use_component=false; Component component if use_component; equation if use_component then component.x = 0; end if; How can I work around this? 回答1: If you want to use condition components, there are some restrictions you need to be aware of. Section 4.4.5 of the Modelica 3.3 specification

问题 I am trying to build a model that will have slightly different equations based on whether or not certain components exist (in my case, fluid ports). A code like the following will not work: parameter Boolean use_component=false; Component component if use_component; equation if use_component then component.x = 0; end if; How can I work around this? 回答1: If you want to use condition components, there are some restrictions you need to be aware of. Section 4.4.5 of the Modelica 3.3 specification

问题 in DOS batch files, In an IF statement, is it possible to combine two or more conditions using AND or OR ? I was not able to find any documentation for that Edit - help if and the MS docs say nothing about using more than one condition in an if. I guess a workaround for AND would be to do if COND1 ( if COND2 ( cmd ) ) but this is exactly what I'm trying to avoid. 回答1: No, there is no easier way. For and you can also just chain them without introducing blocks: if COND1 if COND2 ... which