SUBSTR

Returns a substring from a string value.

Usage: SUBSTR key start end
Complexity: O(N) where N is the length of the returned string. The complexity is ultimately determined by the returned length, but because creating a substring from an existing string is very cheap, it can be considered O(1) for small strings.
Since: 1.0.0
ACL Categories: @read, @slow, @string
Command flags: READONLY

Returns the substring of the string value stored at key, determined by the offsets start and end (both are inclusive). Negative offsets can be used in order to provide an offset starting from the end of the string. So -1 means the last character, -2 the penultimate and so forth.

The function handles out of range requests by limiting the resulting range to the actual length of the string.

Alternative

GETRANGE

Examples

127.0.0.1:6379> SET mykey "This is a string"
OK
127.0.0.1:6379> GETRANGE mykey 0 3
"This"
127.0.0.1:6379> GETRANGE mykey -3 -1
"ing"
127.0.0.1:6379> GETRANGE mykey 0 -1
"This is a string"
127.0.0.1:6379> GETRANGE mykey 10 100
"string"

Replies

RESP2

Bulk string reply: the substring of the string value stored at key, determined by the offsets start and end (both are inclusive).

RESP3