How to extract column from data frame as vector in R ?

# creating a vector for names
names=c('siva nagulu','bhavanarayana','sireesha',
        'priyank chowdary','sridevi','ravi kumar')

# creating a vector for ages
ages=c(40,49,38,42,36,39)

#create a dataframe using these vectors
dataframe=data.frame(names,ages)
print(dataframe)

# converting ages dataframe column into vector
# by passing as index
my_data = dataframe[['names']]
print("--------convert into vector of names column-------")
print(my_data)

my_data = dataframe[['ages']]
print("--------convert into vector of ages column-------")
print(my_data)

# creating a vector for city
city=c('kakumanu','hyd','noida')

# create a dataframe using this vector
dataframe=data.frame(city)
print(dataframe)

# converting city dataframe column into vector
# by passing as index
my_data = dataframe[['city']]
print("--------convert into vector of city column-------")
print(my_data)