# df = dataframe# old.var.name = The name you don't like anymore# new.var.name = The name you want to get
names(df)[names(df)=='old.var.name']<-'new.var.name'
# declaring the columns of data frame
df = data.frame(
col1 = c('A','B','C',NA,'M'),
col2 = c(12.5,9,16.5,20,14.5),
col3 = c(NA,3,2,NA,0))# printing original data frame
print("Original data frame : ")
print(df)# print("Renaming columns names ")# renaming all the column names of data frame
df <- setNames(df, c("changed_Col1","changed_Col2","changed_Col3"))
print("Renamed data frame : ")
print(df)