Programming :: Perl - Pointers To Arrays From Hashes?
Feb 18, 2010
I'm trying to figure out how to code for this specific type of instance - I want to use a hash and have the key be a reference to an array, and not use the key in the standard way of it being a scalar. Basically, I have a large output that I need to process line by line, and rather have access to it as an array than a big block in a scalar. For the big block hash as a scalar I would do -
How would I code it that I would have access to the key information as an array and not a scalar? I know it needs to be a pointer and we're going to have -> in there somewhere, but not sure how to approach it. Some of the documentaiton I've been reading about referencing I've found a little confusing so far, and trying to figure out how to use them in context of what I'm working on.
I am in need of some syntax help. I'm trying to figure out how to store and retrieve an array out of a hash of hashes. For this example, I'm trying to access the city list for a particular state for a particular country. I understand I could do a join and split on the hash key to combine Country and State, but trying to keep things separated.The code I have gets in all the information for the Countries, and states, and gets the list of cities together, no problem. I store all the city names in an array, then make an anonymous pointer to the array for the hash, like this - $MY_CITIES{$COUNTRY}{$STATE} = [@CITIES]I believe that syntax is correct, or is it? What I'd like to do is I need to cycle through every hash to find if a city exists or not. If it exists in 3 states, then it should print 3 times. Here is the code block to search -
Code: for $COUNTRY (@LIST_OF_COUNTRIES) { for $STATE ( keys %MY_CITIES{$COUNTRY){$STATE} ) {
########## some text text also includes empty lines ########## some more text ##########
Basically all sections are separated by 10 hashes and I need to somehow only print all lines in the last section (the "some more text" part in the example above"). I tried all kind of things with sed and awk but I didn't find any way to identify the last "section".
i'm practicing in very basic c programs using the gcc compiler.I found that when i create two variables let's say
Code:
int a,b and Code: a=15; b=3; a=b; b--;
then a equals 2.I thought that this isn't normal in C isn't it?I haven't had the time to read the gcc documentation yet...so i think it has something to do with my compiler's default settings.I use the
Code: gcc filename.c -o filename command to compile
What is the difference between *ptr++ and (*ptr)++. In my opinion the terminology is all over the place so if you could give an example it would be better.
i'm a bit stuck playing with the following class setup for glut. The actual issue is with the function pointers.Basically the following code is the opengl redbook cube example slightly modified.
In the above example, the functions take no input arguments. Can they take a different number of arguments, for example, function_a(int), function_c(int, int), function_e(int, char, int)? How can I do that?
I want to know is there some more efficient way of passing a pointer to a local variable as a parameter to a function in x86 asm? Right now I have to move the base pointer to a temp register, subtract from the register and pass that, like this (assuming a local var at esp-4):
Code: mov eax, ebp sub eax, 4 push eax Is there a better way?
I am trying to find a way to pull Node Pointers out of the model, for use in other areas of the program. The solution is probably simple but I haven't had any luck finding it.
Model for a QTreeView:
Code:
class testModel : public QAbstractItemModel { public: testModel(); ~testModel();
I have the most strange problem ever in programming. I fork a process into a parent and a child. In every forked process i declare a pointer, malloc and define a different value for every pointer.When i printf the value and the address guess what? They both have the SAME ADDRESS but DIFFERENT values, as assigned..Here's the portion of my code:
I have a problem on a program,the problem take a very long time when i try to add two big arrays element by elementI know that matlab make adding vectors more faster than adding element by element but I don't know how!!!do any body knew how matlab make vectors operations more faster than element by element???I want to make my calculation more faster because the program is very big
I was reading Kernighan Ritchie book chapter 4 which deals with character pointers.I am not able to understand following different type of declarations
Code: char aname[][15] = { "Illegal month", "Jan", "Feb", "Mar" }; char amessage[] = "now is the time";
need to process files within multiple directories and transfer these to a remote server. What I had in mind was to use arrays for this; code pasted below (explains it better):
Code: #set the arrays array_A=( fileA* pathtodestA hostA passwordA )
The first two rows of the second column are being replaced into the last two rows of the first column, now I even checked in visual studio and it works fine there. A friend tried my code and he gets it even worse: column 1:
0,0,0,0,1,1,1,1,1,1 column 2: 1,1,1,1,1,1,1,1,1,1
As far as I've seen it must be a problem with GCC, unfortunately I need to have this up and running in GCC no matter what.
I'm making script for automated compiling of one program which would output builds optimized for many architectures. For clearancy, I do each build in it's own catalogue and list of builds with their respective catalogues would be stored as array. I'm using this guide as reference. It describes making array as naming a variable with additional brackets denoting it's position in array.
I have a Perl script that has two arrays - they are related. I would like to print out the contents into two columns next to each other.
#!/usr/bin/perl open(PINGFILE, </home/casper/pingdata.txt") or die " can not open file "; my @totalfile=<PINGFILE>; foreach $string(@totalfile) { if ($string =~ m/(^1sping)(?=.*max))/) { push(usecstring,"$string");
I am working on a project that needs to use structures and I'm pretty sure string arrays. First I declare my structures and they must be exactly like this.
a project using bluetooth to send data byte by byte to external devices buti'm not familiar using arrays to read file from another location before sending the data.If you could,do correct my codes.Here's my code,
I'm writing a code to get the index of the last occurrence of a given substring in a string.
Code: int StringHandler::lastIndexOf(string src, const string s) { unsigned int lastIndex = string::npos; if (src.find(s, 0) == string::npos) { return -1; } else { bool isLast = false; unsigned int i = 0; do { lastIndex = src.find(s, i); if (lastIndex != string::npos) { i = lastIndex + 1; if (i == src.size()) { isLast = true; } } else { isLast = true; } } while (!isLast); } return lastIndex; }
My problem is: execution steps into an if with a false condition! Check the values of i and src.size() at the right panel. How could be possible for the program to run the highlighted statement? The if condition above is false! [URL]. I could use char arrays, for example, but this kind of false validation has happened to me more than once, I'm using G++ 4.5 with these flags: -O0 -g -Wall -c
I just started programming in PHP so I haven't figured out how to do this yet, but I have a multi-dimensional array that I need to sort by one column. That's fine...but I need the sort to ignore case! Right now I have it sorted by 'name' (the other column is 'uid').
The problem is that by the default the sort is case-sensitive so the array looks like this: Code: Apple 4015 Banana 4011 Cherry 4045 avocado 4046
I want to be able to sort the the 'name' column in a case-insensitive manner so that the array actually looks like: Code: Apple 4015 avocado 4046 Banana 4011 Cherry 4045
How to accomplish this? Just FYI I'm not actually sorting the PLUs for fruits...but it was a simple example. I'm actually doing this for a Facebook application.
In my code printf seems to have a problem with elements that have the same letters but a space inbetween. For instance "new foo", "newfoo" are the same for printf
I've got a situation. I'm having GNU bash version 3.00.16(1) on Solaris 10. I need to declare an array say arr1 which will be populated by an output of a command.
declare -a arr1 arr1=( $(/some/command) )
Supposing it will eventually (after executing the command) have element values as -
arr1[0]=1234 arr1[1]=5678 arr1[2]=7890
Now, I need to declare another set of arrays, one for each of the element values above - e.g.
declare -a arr1_1234 declare -a arr1_5678 declare -a arr1_7890
And I also need to populate elements of each of above 3 arrays with output of another command in a loop. So, these arrays will hold values something like -
I'm able to declare and populate arr1[*]. My question is how do I declare, populate and print the subsequent arrays and their elements?I am feeling rather thick to get this working.
