Tcl API Reference -- ns_set

### ns_set

#### Overview

Manipulate sets of key-value pairs

#### Syntax

ns_set copy -persist setId

ns_set cput setId key value

ns_set create -persist name

ns_set delete setId fieldNumber

ns_set delkey setId key

ns_set find setId key

ns_set free setId

ns_set get setId key

ns_set icput setId key value

ns_set idelkey setId key

ns_set ifind setId key

ns_set iget setId key

ns_set isnull setId fieldNumber

ns_set iunique setId key

ns_set key setId fieldNumber

ns_set merge high low

ns_set move to from

ns_set name setId

ns_set new -persist name

ns_set print setId

ns_set put setId key value

ns_set size setId

ns_set split -persist setId ?splitChar?

ns_set truncate setId size

ns_set unique setId key

ns_set update setId key value

ns_set value setId fieldNumber

#### Description

ns_set copy returns a new set that has the same name and key value pairs as the passed-in set (setId). If -persist is specified, the new set will persist even after the current transaction ends, and you can free it later with ns_set free. If -persist is not specified, the new set is automatically freed when the transaction ends.

ns_set cput appends a new field to the set with key key and value value if the field does not already exist in the set. The field number of the new field is returned.

ns_set create (which is the same as ns_set new) allocates memory for a new set and returns the ID for the new set. If -persist is specified, the new set will persist even after the current transaction ends, and you can free it later with ns_set free. If -persist is not specified, the new set is automatically freed when the transaction ends.

ns_set delete deletes the field in the set at field number fieldNumber.

ns_set delkey removes the first field in the set whose key is key. Note that there could be multiple fields in the set with this key; this command only removes the first occurrence.

ns_set find returns the index of the first field in the specified set whose key name matches the specified key. Zero (0) is the index of the first field. If no matching fields are found, ns_set find returns -1.

ns_set free frees the specified set. Sets must be explicitly freed with ns_set free if the -persist option was used when creating the set. Otherwise, sets are automatically freed when the transaction ends.

ns_set get returns the first value associated with the passed-in key. If the key is invalid, an empty string is returned.

ns_set icput is the case-insensitive counterpart of ns_set cput.

ns_set idelkey is the case-insensitive counterpart of ns_set delkey.

ns_set ifind is the case-insensitive counterpart of ns_set find.

ns_set iget is the case-insensitive counterpart of ns_set get.

ns_set isnull returns 1 if the value of the field specified by fieldNumber is null and 0 if it is not. Note that an empty string is not the same as a null. ns_set isnull will return 0 for an empty string.

ns_set iunique returns 1 if the specified key is unique in the specified set and 0 if it is not. The test for uniqueness is performed case-insensitively. ns_set unique is the case-sensitive version of this function.

For example, a client could send multiple "Accept:" headers which would end up in the header set for the connection. ns_set iunique would return 0 for the "Accept:" key, because there are multiple fields with the key "Accept:".

ns_set key extracts the key of the set at field number fieldNumber. This command is useful when looping through all the key-value pairs in the set.

ns_set merge merges two sets. Any fields in the low set are appended to the high set if a field with the same key name does not already exist in the high set.

ns_set move moves all fields from the from set to the end of the to set, leaving the from set a valid, empty set.

ns_set name returns the name of the set.

ns_set new (which is the same as ns_set create) allocates memory for a new set and returns the ID for the new set. If -persist is specified, the new set will persist even after the current transaction ends, and you can free it later with ns_set free. If -persist is not specified, the new set is automatically freed when the transaction ends.

ns_set print prints the specified set to stderr.

ns_set put appends a new field to the set with key key and value value. Note that the field is appended so if a previous field has the same key as the new field, the previous field is returned by ns_set get command. The field number of the new field is returned.

ns_set size returns the number of key-value pairs in the set.

ns_set split splits one set into multiple sets based on the splitChar as described below and returns a Tcl list of the newly-allocated sets. It assumes that the keys in the specified set (setId) contain a specific character (splitChar) that can be used to separate the name of a new set and the key in the new set. The default splitChar is a period (.).

For example, if two fields in the original set have "dog.food" and "cat.food" as their key names and "Yummy dog food!" and "Yummy cat food!" as their values, ns_set split would return two new sets named "dog" and "cat". The dog set would have a single field whose key is "food" and whose value is "Yummy dog food!". The cat set would have a single field whose key is "food" and whose value is "Yummy cat food!".

ns_set truncate reduces the set to the first size key-value pairs and frees the memory for the rest of the key-value pairs that may have been in the set.

ns_set unique returns 1 if the specified key is unique in the specified set and 0 if it is not. The test for uniqueness is performed case-sensitively. ns_set iunique is the case-insensitive version of this function.

ns_set update updates the first field in the specified set whose key is key and replaces its value with value. ns_set update is equivalent to ns_set delkey followed by ns_set put.

ns_set value extracts the value of the set at field number fieldNumber. This command is useful when looping through all the key-value pairs in the set.

#### Notes

The fields in the set are ordered by number. The field numbers range from 0 to one less than the total number of fields. For example, if you have a set with 5 fields, you would use "ns_set key $setid 4" to extract the key of the last field in the set..

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