Replace operation will change existing key-value. If the key-value do not exists we will get an response like NOT_STORED. Its syntax is similar to add.

replace key flags expiretime bytes
value

• replace is the name of the verb
• key the key which replaced
• flag as flag
• expiretime  the time range the key-value stored in memcached
• bytes  the size of the new value
• value new value

Let’s add new data  and check it exists.

add poftut 0 100 4 
test 
STORED 
get poftut 
VALUE poftut 0 4 
test 
END

We will replace poftut key-value with new value.

replace poftut 0 100 7 
testnew 
STORED

• replace  the verb
• poftut  is the key we want to replace its data
• 0 flags
• 100 the second we want to hold new key-value
• 7 is the size of new value
• testnew  is new value
• STORED  the result of the successful replace operation

Python Application

import memcache 
client=memcache.Client([('127.0.0.1',11211)]) 
 
#Add 
samp={"poftut2":"test"} 
client.add("sample",samp,time=1000) 
 
#Replace 
samp={"poftut":"testnew"} 
client.replace("sample",samp,time=1000) 
print(client.get("sample"))

We save the code as filename replace.py.After running the code the output we get.

$ python3 replace.py
{'poftut': 'testnew'}