This is the 10th day of my participation in the August More Text Challenge. For details, see:August is more challenging”

String type is the most basic data type in Redis. It can store any form of string, including binary data, serialized data, jsonized objects and even a picture.

The general idea of string data manipulation is to manipulate value by key, where key is the data id, and value is the business data that we’re interested in.

💍 1 set

  • Syntax: set key value

  • Run the following command to set the string value to a key. If the key already exists, the preceding value will overwrite the preceding value.

  • Return value: OK indicates success

2, get 💎

  • Syntax: get key

  • Run the following command to obtain the string value set in key

  • Return value: key exists, return value corresponding to key;

    Key doesn’t exist, return nil

⚽ 3, append

  • Syntax: append key value

  • Function: Append value to the end of the original value of the key, if the key exists

    If the key does not exist, the key is set to value

  • Return value: total length (number of characters) after the append string

⚾ 4, strlen

  • Syntax: strlen key

  • Function: returns the length of the string value stored by key

  • Return value: The length of the string value if the key exists;

Key does not exist, return 0

🥎 5, incr

  • Syntax: incr key

  • Run the following command to increment the numeric value stored in the key by 1. If the key does not exist, the value of the key is initialized to 0 before the incr operation is performed.

  • Return value: returns the key value incremented by 1

🏀 6, decr

  • Syntax: decr key

  • If the key does not exist, then the value of the key is initialized to 0 before the decr operation is performed.

  • Return value: Returns the key value minus 1

7, incrby 🎯

  • Syntax: incrby key offset

  • Run the following command to add an increment value to the stored value of the key. If the key does not exist, the value of the key is initialized to 0 and then the INCRBY command is executed.

  • Return value: Returns the value of the key after the increment.

8, decrby 🏸

  • Syntax: decrby key offset

  • Run the DECRBY command to subtract the decrement value from the stored key. If the key does not exist, the value of the key is initialized to 0 before the DECRBY command is executed.

  • Return value: Returns the decrement value of the key.

Nine, getrange 🏓

  • Syntax: getrange key startIndex endIndex

  • Run the following command to obtain the substring of the key from startIndex to endIndex, including startIndex and endIndex. A negative number indicates that the value starts from the end of the string, and -1 indicates the last character.

10, setrange 🥊

  • Syntax: setrange key offsetIndex value

  • Function: Overwrite the stored value of the key with value starting with offset.

  • Return value: the length of the modified string.

🥋 11, setex

  • Syntax: setex key seconds value

  • Run the following command to set the value of the key and set the lifetime of the key to seconds. If the key already exists, the old value is overwritten.

  • Return value: Set successfully, return OK.

12, setnx ⛳

  • Syntax: setnx key value

  • Function: setnx is short for set if Not exists. If the key does not exist, the value is set. If the key does exist, the value is not set.

  • Return value: 1 on success, 0 on failure

13, mset 🥇

  • Syntax: mset key value [key value…

  • Run the following command to set one or more key-value pairs at the same time

  • Return value: Set successfully, return OK.

14 and mget 🥈

  • Syntax: mget key [key…]

  • Function: Gets all (one or more) values of a given key

  • Return value: a list of all keys, or nil if the key does not exist.

15, msetnx 🏆

  • Syntax: msetnx key value[key value…

  • Run the following command to set one or more key-value pairs at the same time. If one key exists, the setting fails.

  • Return value: set successfully, return 1

Failed to set. 0 is returned