Programming :: Python Equivalent Of C Ternary Operator?
Jun 12, 2010
I've been reading and googling, etc. I've seen some things, but not a definite explanation of this. What is the appropriate way to mimic a C ternary operator using Python? Isn't there an exact proper way to do it? Any difference for using lambda functions? I'm sorry, but I've been searching and it's ambiguous to me how this should be handled. I would appreciate a person's help on this. I came up with this link, but I'm wondering if I'm missing something.[URL]...
So, is that it? In Dive Into Python, it's using the and-or trick. Well, if the above post is the full explanation,
I'm having a bit of an issue using overloaded operators in an already overloaded operator. In my following code, I have overloaded the && operator to compare two Course objects. The operator in turn goes to a function which calls other overloaded operators to compare private object variables of that object to compare them.
Is there a python equivalent for the "array_unique" function in php?
I have to run a query on a very large table (1.5 million records, with no index!) and php can't beat the max execution time. So I am converting my php script to python, which I have never used before.
my php script basically does this:
gets results from database gets the number of unique values in column "X" counts how many times each unique value in column "X" occurs echos the results
My php script was originally running on a smaller version of the table, I would have started in python if I would have known the "real" table was so large, python is the only language I have access to in my current environment (besides php).
I have a binary value which I receive from a controller. Say this binary value is 42. Just plain hex 42. If you would look at that byte in a debugger you would see 42.Now this value hold 8 bits each indicating a high or a low output. So 0x42 = 01000010b. Which means bits 1 and 6 are '1'.When I would want to find out which bits are set and which are not in a language like C, I simply do:
Code:
mask = 0x80; if (binval & mask) {...} etc..
However I am programming in TCL, and I try to do:
Code:
set mask 0x80 if { [expr ($binval & $mask) > 0] } {...} etc...
this fails. At the moment the expr is executed, $binval is evaluated and substituted so the expression I am evaluating is
Code:
set mask 0x80 if { [expr ('B' & '0x80') > 0] } {...} etc...
Eventually I got it working by converting the $binval into a '0x42' string value, like this:
Code:
binary scan $binval c byte set byte [format "0x%0x" $byte] set mask 0x80 if { [expr ($byte & $mask) > 0] } {...} etc...[
Then the expression yields what I want. But this seems so stupid and clumsy. Isn't there a better way where I can compare two binary values without conversions?
I have a simple program from book C++ cookbook, page 291, 8.3, Using Constructors and Destructors to manage resources (or RAII), but it can not get compiled in my g++
------------------------------------------------------------------------------------------------ // Example 8-3. Using constructors and destructors #include <iostream> #include <string> using namespace std;
I'm very new at Bash scripting and have a bone head issue that I'm trying (and failing) to resolve. I cannot get this one IF statement to work, it seems the comparison operator does not think the resulting number from the $b*$c+$b operation is an integer even though it is a number. Below is a small proof of concept script with the bit I'm having trouble with.
Is there a way to achieve the following with the square bracket operator?I have a class:
Code: Select allclass A { public: void SetValue(int index, Item* B); private: int m_iCount; ItemCollection Item_Collection;
[code]....
The probelm is that I am not just blindly assigning whatever given on the right hand side to the returned value from operator [], I need to verify it's not NULL, and it is not already there in the Item_Collection, and I also need to increase the count.
I know it is wrong to use the "==" operator to compare the equality of two floating point numbers. Logically it would seem that if the "==" operator is not usable for floating point comparison, then the "<=" operator would also not be usable. Is this true? The lack of google search results on this topic made me think that it must be true. If that is true, then is it true that the only way to compare floats with <= or >= is with something like the code below? Code: bool smaller_than_or_equal(float a, float b) {
if ( fabs(a-b) < EPSILON){return true;} else if (a < b) {return true;} else {return false;}
} I think this is a general question, but if specifics are necessary, I am using the C++ language to code at the moment.
I am trying to learn C++.I implemented a simple archive program, and I am in a situation in which the user is prompted by a menu to make a choice.So I have some cout instruction to illustrate the possible choices and then
int choice; cin>>choice;
and everything works fine.I introduced this code in a "while" loop that checks wether the choice made by the user is valid or not:
bool check=true; int choice; while(check) { cin>>choice; if(the choice is valid) {...;check=false} else cout<<"please make an other choice" }
What is happening is that if by mistake the user introduces a character in place of a number, the loop repeats indefinitely because the program, when it get to the "cin" instruction, does not pauses to wait for a new input.
Can one of you point me towards a comprehensive print function tutorial in perl? I was under the impression that everything within quotes will get interpolated - but I am running into exceptions where it is not desirable to run some varaibles under quotes.
which definitly is not the same number. I guess somewhere in the convertion from double to char* ("<<") something is not right and what can i do to save these double numbers in an accurate manner in a file?
does the assignment operator copy all the members also for structures containing STL objects strings,vectors,vectors of vectors...)? I did try it on my platform,and it works that way (copying all the fields),but i was wondering if it is a standard behavior or not.
I'd like to try a gnome applet named DockbarX. It has some dependecies, and it lists them by their debian package names. I couldn't find an equvivalent package for "python-gnome2-desktop". I suppose it contains python bindings for gnome. Can some help me? Also, is there a general naming pattern that helps with guessing package names?
I have a function definition in a Python 2.x script which take a tuple as one of its arguments, but 2to3 has no answers nor any of my searching on how to represent the same in Python 3.x
My compiler won't find <new>. Since it's such a basic function, I'm a bit confused. Is <new> supposed to be in a file of its own? Where do I find it? And if it turns out to be missing on my computer, where can I find a <new> one? Or do you see anything else that I do wrong?
After some trying out, it seems I can't find stuff like iostream or any other basic stuff either. The compiler is prolly looking for them at the wrong place. Does anyone know how I change or add paths for the compiler to look in when using the "<>" operator?
I want that I click with the mouse on the video, it paused.I notice that there is "BaconVideoWidget" which I guess is the video rendering widget but it don't have signal named "clicked":
I have a python script I wrote a while ago and now I would like to call that script from inside C. I know how to do one command from C, but how would you execute an entire script from C, and passing arguments? Like:
I have decided to learn python as it seems to be powerful not just for web development (like php) but also a clean powerful language for other puposes.
Q: Can someone suggest a tutorial or book, on learning python (beginner to intermediate) which has as its focus for learning, web development?
In order of preference: 1. Comprehensive, 2. Online, 3. Free
