mongo.bson.iterator.next: Advance an iterator to the first or next field

In jonkatz2/rmongodb: R-MongoDB driver

Description

Advance a mongo.bson.iterator to the first or next field.

Usage

mongo.bson.iterator.next(iter)

Arguments

iter	A mongo.bson.iterator.

Value

(integer) The type of the next of the field pointed to by the iterator as indicated by the folllowing constants:

• mongo.bson.eoo – End of Object (0L)

• mongo.bson.double

• mongo.bson.string

• mongo.bson.object

• mongo.bson.array

• mongo.bson.binary

• mongo.bson.undefined

• mongo.bson.oid

• mongo.bson.bool

• mongo.bson.date

• mongo.bson.null

• mongo.bson.regex

• mongo.bson.dbref – deprecated (follow link for more info)

• mongo.bson.code

• mongo.bson.symbol

• mongo.bson.code.w.scope

• mongo.bson.int

• mongo.bson.timestamp

• mongo.bson.long

See Also

mongo.bson.iterator,
mongo.bson.iterator.create,
mongo.bson.find,
mongo.bson.iterator.key,
mongo.bson.iterator.type,
mongo.bson.iterator.value,
mongo.bson.

Examples

buf <- mongo.bson.buffer.create()
# Append a string
mongo.bson.buffer.append(buf, "name", "Joe")
# Append a date/time
mongo.bson.buffer.append(buf, "created", Sys.time())
# Append a NULL
mongo.bson.buffer.append(buf, "cars", NULL)
b <- mongo.bson.from.buffer(buf)

iter <- mongo.bson.iterator.create(b)
# Advance to the "cars" field
while (mongo.bson.iterator.next(iter) != mongo.bson.null)
{
    # NOP
}
print(mongo.bson.iterator.value(iter))

# The above is given for illustrative purposes, but may be performed
# much easier by the following:
iter <- mongo.bson.find(b, "cars")
print(mongo.bson.iterator.value(iter))

# iterate through all values and print them with their keys (names)
iter <- mongo.bson.iterator.create(b)
while (mongo.bson.iterator.next(iter)) { # eoo at end stops loop
    print(mongo.bson.iterator.key(iter))
    print(mongo.bson.iterator.value(iter))
}

jonkatz2/rmongodb documentation built on May 19, 2019, 7:30 p.m.