Yes, although PERL and python can look a lot like C, I figured C.
It does seem to be a find/optional insert if missing, hash map/table routine, with linked list buckets, but I am not familiar with passing an array and its length that way. It seems like if the elements char* can be copied, why not just copy the array char** to a pointer element? Let's try something more simple and legal:
It'd be nice if it had the call format like bsearch, tsearch but then it would be hsearch()! https://www.unix.com/man-page/opensolaris/3c/hsearch/
Hi,
For one of my programs, I need to have a hashtable as in Perl. Unfortunately shell doesnt provide any variable like hash. Is there anyway/trick, I could implement a hash in shell (using shell scripts/sed/awk).
JP (2 Replies)
Hello List,
Iam searching for a solution where i can use hash based searching .
In Detail , I have linked list which will be dynamically increasing .
I need a best searching mechanisim such a way that it can take only one itereation .
Right now iam using linear search which is taking... (11 Replies)
Dear Friends,
I want to create a hash table using the standard Glib header (if possible) so that I can store a structure and keep the hash key(search key) based on a string.
Any example code would be great since I am not able to get the main idea.
best regards
Skull (4 Replies)
Hi,
I have a nested hash table say for example as follows:
%coins =
(
1 => {
"Quarter"=>25,
"Dime"=>10,
"Nickel"=>5,
},
2 => {
"asd"=>34,
"qwe"=>45,
... (0 Replies)
hello,
I am creating a HASH table using file1.pl :-
I want to retrieve the content of the hash table created above from another file named file2.pl :-
The problem is that if I separate like this into 2 files.Then it says that HASH table is not created.So can you please tell me how to... (2 Replies)
Hi, i want to implement hash table (put, get and transfer operations) using c in unix. so give some nice infromation on how to write my code. (1 Reply)
Hi,
I hope someone can help me with the following prob..
I need to implement a hashtable whose KEYs are strings and VLAUEs are
again hashtables.
ie key - is a string and value -is another hashtable .
So.... how am I supposed to be implementing my nested hashtable?
Thanks in advance (1 Reply)
Hi all,
I just downloaded this example from the net. I was looking around for a hash table like implementation in unix when I came across this.
ARRAY=( "cow:moo"
"dinosaur:roar"
"bird:chirp"
"bash:rock" )
for animal in ${ARRAY} ; do
KEY=${animal%%:*}
... (8 Replies)
hello,
i am new to scripting and would like to know how to return a hash table from a sub routine.
i tried the following,
my %hash_function = ();
hash_function = &return_hash();
sub return_hash
{
my %hash = ();
///populate the hash
return %hash;
}
but it dosent seem to... (1 Reply)
Hi, I have a hash of hash where it has
name, activities and count
i have data like this -
$result->{$name}->{$activities} = $value;
content of that are -
name - robert tom cat peter
activities - running, eating, sleeping , drinking, work
i need to print output as below
... (3 Replies)
Discussion started by: asak
3 Replies
LEARN ABOUT REDHAT
hsearch
HSEARCH(3) Linux Programmer's Manual HSEARCH(3)NAME
hcreate, hdestroy, hsearch - hash table management
SYNOPSIS
#include <search.h>
int hcreate(size_t nel);
ENTRY *hsearch(ENTRY item, ACTION action);
void hdestroy(void);
#define _GNU_SOURCE
#include <search.h>
int hcreate_r(size_t nel, struct hsearch_data *tab);
int *hsearch_r(ENTRY item, ACTION action, ENTRY **ret, struct hsearch_data *tab);
void hdestroy_r(struct hsearch_data *tab);
DESCRIPTION
The three functions hcreate, hsearch, and hdestroy allow the user to create a hash table (only one at a time) which associates a key with
any data. The three functions hcreate_r, hsearch_r, hdestroy_r are reentrant versions that allow the use of more than one table.
First the table must be created with the function hcreate(). The argument nel is an estimate of the maximum number of entries in the ta-
ble. The function hcreate() may adjust this value upward to improve the performance of the resulting hash table.
The corresponding function hdestroy() frees the memory occupied by the hash table so that a new table can be constructed.
The argument item is of type ENTRY, which is a typedef defined in <search.h> and includes these elements:
typedef struct entry {
char *key;
void *data;
} ENTRY;
The field key points to the NUL-terminated string which is the search key. The field data points to the data associated with that key.
The function hsearch() searches the hash table for an item with the same key as item (where "the same" is determined using strcmp(3)), and
if successful returns a pointer to it. The argument action determines what hsearch() does after an unsuccessful search. A value of ENTER
instructs it to insert a copy of item, while a value of FIND means to return NULL.
RETURN VALUE
hcreate() and hcreate_r() return 0 when allocation of the memory for the hash table fails, nonzero otherwise.
hsearch() returns NULL if action is ENTER and the hash table is full, or action is FIND and item cannot be found in the hash table.
hsearch_r() returns 0 if action is ENTER and the hash table is full, and nonzero otherwise.
ERRORS
ENOMEM Out of memory.
CONFORMS TO
The functions hcreate, hsearch, and hdestroy are from SVID, and are described in POSIX 1003.1-2001. The functions hcreate_r, hsearch_r,
hdestroy_r are GNU extensions.
BUGS
SVID and POSIX 1003.1-2001 specify that action is significant only for unsuccessful searches, so that an ENTER should not do anything for a
successful search. The libc and glibc implementations update the data for the given key in this case.
Individual hash table entries can be added, but not deleted.
EXAMPLE
The following program inserts 24 items in to a hash table, then prints some of them.
#include <stdio.h>
#include <search.h>
char *data[] = { "alpha", "bravo", "charlie", "delta",
"echo", "foxtrot", "golf", "hotel", "india", "juliet",
"kilo", "lima", "mike", "november", "oscar", "papa",
"quebec", "romeo", "sierra", "tango", "uniform",
"victor", "whisky", "x-ray", "yankee", "zulu"
};
int main() {
ENTRY e, *ep;
int i;
/* starting with small table, and letting it grow does not work */
hcreate(30);
for (i = 0; i < 24; i++) {
e.key = data[i];
/* data is just an integer, instead of a
pointer to something */
e.data = (char *)i;
ep = hsearch(e, ENTER);
/* there should be no failures */
if (ep == NULL) {
fprintf(stderr, "entry failed
");
exit(1);
}
}
for (i = 22; i < 26; i++) {
/* print two entries from the table, and
show that two are not in the table */
e.key = data[i];
ep = hsearch(e, FIND);
printf("%9.9s -> %9.9s:%d
", e.key,
ep ? ep->key : "NULL",
ep ? (int)(ep->data) : 0);
}
return 0;
}
SEE ALSO bsearch(3), lsearch(3), tsearch(3), malloc(3)GNU 2001-12-26 HSEARCH(3)