library (readr)

urlfile="https://vincentarelbundock.github.io/Rdatasets/csv/nycflights13/airports.csv"

mydata<-read_csv(url(urlfile))
## New names:
## Rows: 1458 Columns: 9
## ── Column specification
## ──────────────────────────────────────────────────────── Delimiter: "," chr
## (4): faa, name, dst, tzone dbl (5): ...1, lat, lon, alt, tz
## ℹ Use `spec()` to retrieve the full column specification for this data. ℹ
## Specify the column types or set `show_col_types = FALSE` to quiet this message.
## • `` -> `...1`
head(mydata)
## # A tibble: 6 × 9
##    ...1 faa   name                             lat   lon   alt    tz dst   tzone
##   <dbl> <chr> <chr>                          <dbl> <dbl> <dbl> <dbl> <chr> <chr>
## 1     1 04G   Lansdowne Airport               41.1 -80.6  1044    -5 A     Amer…
## 2     2 06A   Moton Field Municipal Airport   32.5 -85.7   264    -6 A     Amer…
## 3     3 06C   Schaumburg Regional             42.0 -88.1   801    -6 A     Amer…
## 4     4 06N   Randall Airport                 41.4 -74.4   523    -5 A     Amer…
## 5     5 09J   Jekyll Island Airport           31.1 -81.4    11    -5 A     Amer…
## 6     6 0A9   Elizabethton Municipal Airport  36.4 -82.2  1593    -5 A     Amer…
library(dplyr)
## 
## 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
summary(mydata)
##       ...1            faa                name                lat       
##  Min.   :   1.0   Length:1458        Length:1458        Min.   :19.72  
##  1st Qu.: 365.2   Class :character   Class :character   1st Qu.:34.26  
##  Median : 729.5   Mode  :character   Mode  :character   Median :40.09  
##  Mean   : 729.5                                         Mean   :41.65  
##  3rd Qu.:1093.8                                         3rd Qu.:45.07  
##  Max.   :1458.0                                         Max.   :72.27  
##       lon               alt                tz              dst           
##  Min.   :-176.65   Min.   : -54.00   Min.   :-10.000   Length:1458       
##  1st Qu.:-119.19   1st Qu.:  70.25   1st Qu.: -8.000   Class :character  
##  Median : -94.66   Median : 473.00   Median : -6.000   Mode  :character  
##  Mean   :-103.39   Mean   :1001.42   Mean   : -6.519                     
##  3rd Qu.: -82.52   3rd Qu.:1062.50   3rd Qu.: -5.000                     
##  Max.   : 174.11   Max.   :9078.00   Max.   :  8.000                     
##     tzone          
##  Length:1458       
##  Class :character  
##  Mode  :character  
##                    
##                    
## 
mydatastats<- {
  mydata%>%
  summarize(AvgAlt=mean(alt),
            MedianAlt=median(alt),
            AvgTZ=mean(tz),
            MedianTZ=median(tz))}
mydatastats
## # A tibble: 1 × 4
##   AvgAlt MedianAlt AvgTZ MedianTZ
##    <dbl>     <dbl> <dbl>    <dbl>
## 1  1001.       473 -6.52       -6
airport<- mydata[,c(3,6,7,9)]
names(airport)[1] <- "apt"
names(airport)[2] <- "tude"
names(airport)[3] <- "gmt"
names(airport)[4] <- "Time Zone"

View(airport)
summary(airport)
##      apt                 tude              gmt           Time Zone        
##  Length:1458        Min.   : -54.00   Min.   :-10.000   Length:1458       
##  Class :character   1st Qu.:  70.25   1st Qu.: -8.000   Class :character  
##  Mode  :character   Median : 473.00   Median : -6.000   Mode  :character  
##                     Mean   :1001.42   Mean   : -6.519                     
##                     3rd Qu.:1062.50   3rd Qu.: -5.000                     
##                     Max.   :9078.00   Max.   :  8.000
airportstats<-{
airport%>%
  summarize(newavgAlt=mean(tude),
            newmedAlt=median(tude),
            newavgTZ=mean(gmt),
            newmedTZ=median(gmt))}
#comparing median and avg's from source data with data frame

airportstats 
## # A tibble: 1 × 4
##   newavgAlt newmedAlt newavgTZ newmedTZ
##       <dbl>     <dbl>    <dbl>    <dbl>
## 1     1001.       473    -6.52       -6
mydatastats
## # A tibble: 1 × 4
##   AvgAlt MedianAlt AvgTZ MedianTZ
##    <dbl>     <dbl> <dbl>    <dbl>
## 1  1001.       473 -6.52       -6
airport["tude"][airport["tude"]<1000] <- 0

airport["Time Zone"][airport["Time Zone"]=="America/New_York"] <- "America/NYC"

airport["gmt"][airport["gmt"]== -5] <- 24

View(airport)
View(airport)