go - Can't create copy of variable of type map[int]Struct in another variable by just assigning one variable to another -

i have map :

cart := map[10033207:{10033207 3 425 126} 10012761:{10012761 4 40 0}] 

i want create copy of cart in variable tempcart can modify tempcart temporary usage in function. want cart value remains same.

tempcart := cart //some operation modifies temp cart , make //map[10033207:{10033207 2 425 126} 10012761:{10012761 1 40 0}] 

the problem when modify tempcart, somehow cart getting modified , becomes equal tempcart.

later when print value of cart get: map[10033207:{10033207 2 425 126} 10012761:{10012761 1 40 0}] , not original value map[10033207:{10033207 3 425 126} 10012761:{10012761 4 40 0}].

i can't understand reason behind , want know solution of how create copy of cart.

edit: question has been marked duplicate copy 1 map another knew how copy 1 map anothor, prime question why couldn't assign 1 map variable. why have copy in loop.

to copy map use

for k,v := range originalmap {   newmap[k] = v }