Get the entire dataset in bridge_data and the add column names to each data column and then read table in bridge_tbl and then find the summary of the new table and few data from the table. Then to manupulate or work with a smaller dataset we can slice the dataset into subset and work on it as bridge_sub
bridge_data <- url("https://archive.ics.uci.edu/ml/machine-learning-databases/bridges/bridges.data.version1","r")
colNames<-c("IDENTIF","RIVER","LOCATION","ERECTED","PURPOSE","LENGTH","LANES","CLEAR-G","T-OR-D","MATERIAL","SPAN","REL-L","TYPE")
bridge_tbl<-read.table(bridge_data,sep=",",dec=".",col.names=colNames,na.strings=c("NA", "-", "?"," "),stringsAsFactors=FALSE)
summary(bridge_tbl)## IDENTIF RIVER LOCATION ERECTED
## Length:108 Length:108 Min. : 1.00 Min. :1818
## Class :character Class :character 1st Qu.:15.50 1st Qu.:1884
## Mode :character Mode :character Median :27.00 Median :1903
## Mean :25.98 Mean :1905
## 3rd Qu.:37.50 3rd Qu.:1928
## Max. :52.00 Max. :1986
## NA's :1
## PURPOSE LENGTH LANES CLEAR.G
## Length:108 Min. : 804 Min. :1.00 Length:108
## Class :character 1st Qu.:1000 1st Qu.:2.00 Class :character
## Mode :character Median :1300 Median :2.00 Mode :character
## Mean :1567 Mean :2.63
## 3rd Qu.:2000 3rd Qu.:4.00
## Max. :4558 Max. :6.00
## NA's :27 NA's :16
## T.OR.D MATERIAL SPAN
## Length:108 Length:108 Length:108
## Class :character Class :character Class :character
## Mode :character Mode :character Mode :character
##
##
##
##
## REL.L TYPE
## Length:108 Length:108
## Class :character Class :character
## Mode :character Mode :character
##
##
##
## head(bridge_tbl)## IDENTIF RIVER LOCATION ERECTED PURPOSE LENGTH LANES CLEAR.G T.OR.D
## 1 E1 M 3 1818 HIGHWAY NA 2 N THROUGH
## 2 E2 A 25 1819 HIGHWAY 1037 2 N THROUGH
## 3 E3 A 39 1829 AQUEDUCT NA 1 N THROUGH
## 4 E5 A 29 1837 HIGHWAY 1000 2 N THROUGH
## 5 E6 M 23 1838 HIGHWAY NA 2 N THROUGH
## 6 E7 A 27 1840 HIGHWAY 990 2 N THROUGH
## MATERIAL SPAN REL.L TYPE
## 1 WOOD SHORT S WOOD
## 2 WOOD SHORT S WOOD
## 3 WOOD <NA> S WOOD
## 4 WOOD SHORT S WOOD
## 5 WOOD <NA> S WOOD
## 6 WOOD MEDIUM S WOODbridge_sub<-bridge_tbl[,c(1,3,5,7,9,11)]
summary(bridge_sub)## IDENTIF LOCATION PURPOSE LANES
## Length:108 Min. : 1.00 Length:108 Min. :1.00
## Class :character 1st Qu.:15.50 Class :character 1st Qu.:2.00
## Mode :character Median :27.00 Mode :character Median :2.00
## Mean :25.98 Mean :2.63
## 3rd Qu.:37.50 3rd Qu.:4.00
## Max. :52.00 Max. :6.00
## NA's :1 NA's :16
## T.OR.D SPAN
## Length:108 Length:108
## Class :character Class :character
## Mode :character Mode :character
##
##
##
## head(bridge_sub)## IDENTIF LOCATION PURPOSE LANES T.OR.D SPAN
## 1 E1 3 HIGHWAY 2 THROUGH SHORT
## 2 E2 25 HIGHWAY 2 THROUGH SHORT
## 3 E3 39 AQUEDUCT 1 THROUGH <NA>
## 4 E5 29 HIGHWAY 2 THROUGH SHORT
## 5 E6 23 HIGHWAY 2 THROUGH <NA>
## 6 E7 27 HIGHWAY 2 THROUGH MEDIUMclose(bridge_data)