Prictice Assignment 6

library(nycflights13)

## Warning: package 'nycflights13' was built under R version 3.4.2

library(dplyr)

## Warning: package 'dplyr' was built under R version 3.4.2

## 
## Attaching package: 'dplyr'

## The following objects are masked from 'package:stats':
## 
##     filter, lag

## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union

flights.tbl<-tbl_df(flights)

1. Display the “min, max,avg” flight time and avg distance traveled of United Air

flights departinf JFK March of 2013

flights.tbl%>%
  filter(origin=="JFK",month==3,carrier=="UA",air_time,distance)%>%
  summarise(minfltime=min(air_time,na.rm=TRUE),
            maxfltime=max(air_time,na.rm=TRUE),
            avgfltime=mean(air_time,na.rm=TRUE),
            avgdistance=mean(distance,na.rm=TRUE))

## # A tibble: 1 x 4
##   minfltime maxfltime avgfltime avgdistance
##       <dbl>     <dbl>     <dbl>       <dbl>
## 1       281       394  342.9253    2534.792

2. Display the “min,max,avg” departure delays in minutes for June 2013

grouped by airports JKF,EWR,LGA.

flight_dely<-filter(select(flights,dep_delay,month,origin))
june_delay<-filter(flight_dely,dep_delay>0,month==6)  
june_delay%>%
  group_by(origin)%>%
  summarise(min_delay=min(dep_delay,na.rm=TRUE),
            max_delay=max(dep_delay,na.rm=TRUE),
            avg_delay=mean(dep_delay,na.rm=TRUE))

## # A tibble: 3 x 4
##   origin min_delay max_delay avg_delay
##    <chr>     <dbl>     <dbl>     <dbl>
## 1    EWR         1       502  47.92212
## 2    JFK         1      1137  47.98522
## 3    LGA         1       803  54.96745

3. Dispaly “min,max,avg” mile traveled per hour for United Airlines and American Airlines flights flying between JFK,EWR,LGA and Chicago O’Hare in June,July, August 2013.

fltr_dtatset<-filter(select(flights.tbl,carrier,origin,air_time,month,dest,distance))
final<-filter(fltr_dtatset, air_time,distance, carrier== c("UA","AA") & dest== "ORD" & month %in% c("6","7","8"))
    mph<-mutate(final,mph=distance/(air_time/60))
    summarise(mph,min_mph= min(na.rm=TRUE,mph ),
          max_mph=max(na.rm=TRUE,mph ),
          avg_mph=mean(na.rm=TRUE,mph))

## # A tibble: 1 x 3
##    min_mph  max_mph  avg_mph
##      <dbl>    <dbl>    <dbl>
## 1 231.4737 495.8621 396.5622