data maipulation

Code for quiz number 5 -practicingwith dplyr functions

Load libraries we need:
```
 library(tidyverse)
```

Read the data in the filedrug_cos.csv to R and assign it to drug_cos

drug_cos <- read_csv("https://estanny.com/static/week5/drug_cos.csv")

Use glimpse() to view your data
```
glimpse(drug_cos)
```

Rows: 104
Columns: 9
$ ticker       <chr> "ZTS", "ZTS", "ZTS", "ZTS", "ZTS", "ZTS", "ZTS"~
$ name         <chr> "Zoetis Inc", "Zoetis Inc", "Zoetis Inc", "Zoet~
$ location     <chr> "New Jersey; U.S.A", "New Jersey; U.S.A", "New ~
$ ebitdamargin <dbl> 0.149, 0.217, 0.222, 0.238, 0.182, 0.335, 0.366~
$ grossmargin  <dbl> 0.610, 0.640, 0.634, 0.641, 0.635, 0.659, 0.666~
$ netmargin    <dbl> 0.058, 0.101, 0.111, 0.122, 0.071, 0.168, 0.163~
$ ros          <dbl> 0.101, 0.171, 0.176, 0.195, 0.140, 0.286, 0.321~
$ roe          <dbl> 0.069, 0.113, 0.612, 0.465, 0.285, 0.587, 0.488~
$ year         <dbl> 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018,~

Use distinct() to subset distinct rows
```
drug_cos %>%
  distinct(year)
```

# A tibble: 8 x 1
   year
  <dbl>
1  2011
2  2012
3  2013
4  2014
5  2015
6  2016
7  2017
8  2018

Use count() to count observations
```
drug_cos %>%
  count(year)
```

# A tibble: 8 x 2
   year     n
  <dbl> <int>
1  2011    13
2  2012    13
3  2013    13
4  2014    13
5  2015    13
6  2016    13
7  2017    13
8  2018    13

drug_cos %>%
  count(name)

# A tibble: 13 x 2
   name                        n
   <chr>                   <int>
 1 AbbVie Inc                  8
 2 Allergan plc                8
 3 Amgen Inc                   8
 4 Biogen Inc                  8
 5 Bristol Myers Squibb Co     8
 6 ELI LILLY & Co              8
 7 Gilead Sciences Inc         8
 8 Johnson & Johnson           8
 9 Merck & Co Inc              8
10 Mylan NV                    8
11 PERRIGO Co plc              8
12 Pfizer Inc                  8
13 Zoetis Inc                  8

drug_cos %>%
  count(ticker, name)

# A tibble: 13 x 3
   ticker name                        n
   <chr>  <chr>                   <int>
 1 ABBV   AbbVie Inc                  8
 2 AGN    Allergan plc                8
 3 AMGN   Amgen Inc                   8
 4 BIIB   Biogen Inc                  8
 5 BMY    Bristol Myers Squibb Co     8
 6 GILD   Gilead Sciences Inc         8
 7 JNJ    Johnson & Johnson           8
 8 LLY    ELI LILLY & Co              8
 9 MRK    Merck & Co Inc              8
10 MYL    Mylan NV                    8
11 PFE    Pfizer Inc                  8
12 PRGO   PERRIGO Co plc              8
13 ZTS    Zoetis Inc                  8

Use Filter() to extract rows in non-consecutive years

drug_cos %>%
  filter(year %in% c(2013, 2018))

# A tibble: 26 x 9
   ticker name       location ebitdamargin grossmargin netmargin   ros
   <chr>  <chr>      <chr>           <dbl>       <dbl>     <dbl> <dbl>
 1 ZTS    Zoetis Inc New Jer~        0.222       0.634     0.111 0.176
 2 ZTS    Zoetis Inc New Jer~        0.379       0.672     0.245 0.326
 3 PRGO   PERRIGO C~ Ireland         0.236       0.362     0.125 0.19 
 4 PRGO   PERRIGO C~ Ireland         0.178       0.387     0.028 0.088
 5 PFE    Pfizer Inc New Yor~        0.634       0.814     0.427 0.51 
 6 PFE    Pfizer Inc New Yor~        0.34        0.79      0.208 0.221
 7 MYL    Mylan NV   United ~        0.228       0.44      0.09  0.153
 8 MYL    Mylan NV   United ~        0.258       0.35      0.031 0.074
 9 MRK    Merck & C~ New Jer~        0.282       0.615     0.1   0.123
10 MRK    Merck & C~ New Jer~        0.313       0.681     0.147 0.206
# ... with 16 more rows, and 2 more variables: roe <dbl>, year <dbl>

Extract every other year form 2012 to 2018

drug_cos %>%
  filter(year %in% seq(2012, 2018, by = 2 ))

# A tibble: 52 x 9
   ticker name      location ebitdamargin grossmargin netmargin    ros
   <chr>  <chr>     <chr>           <dbl>       <dbl>     <dbl>  <dbl>
 1 ZTS    Zoetis I~ New Jer~        0.217       0.64      0.101  0.171
 2 ZTS    Zoetis I~ New Jer~        0.238       0.641     0.122  0.195
 3 ZTS    Zoetis I~ New Jer~        0.335       0.659     0.168  0.286
 4 ZTS    Zoetis I~ New Jer~        0.379       0.672     0.245  0.326
 5 PRGO   PERRIGO ~ Ireland         0.226       0.345     0.127  0.183
 6 PRGO   PERRIGO ~ Ireland         0.157       0.371     0.059  0.104
 7 PRGO   PERRIGO ~ Ireland        -0.791       0.389    -0.76  -0.877
 8 PRGO   PERRIGO ~ Ireland         0.178       0.387     0.028  0.088
 9 PFE    Pfizer I~ New Yor~        0.447       0.82      0.267  0.307
10 PFE    Pfizer I~ New Yor~        0.359       0.807     0.184  0.247
# ... with 42 more rows, and 2 more variables: roe <dbl>, year <dbl>

Extract tickers “PFE” and “MYL”

drug_cos %>% 
  filter(ticker %in% c("PFE", "MYL"))

# A tibble: 16 x 9
   ticker name       location ebitdamargin grossmargin netmargin   ros
   <chr>  <chr>      <chr>           <dbl>       <dbl>     <dbl> <dbl>
 1 PFE    Pfizer Inc New Yor~        0.371       0.795     0.164 0.223
 2 PFE    Pfizer Inc New Yor~        0.447       0.82      0.267 0.307
 3 PFE    Pfizer Inc New Yor~        0.634       0.814     0.427 0.51 
 4 PFE    Pfizer Inc New Yor~        0.359       0.807     0.184 0.247
 5 PFE    Pfizer Inc New Yor~        0.289       0.803     0.142 0.183
 6 PFE    Pfizer Inc New Yor~        0.267       0.767     0.137 0.158
 7 PFE    Pfizer Inc New Yor~        0.353       0.786     0.406 0.233
 8 PFE    Pfizer Inc New Yor~        0.34        0.79      0.208 0.221
 9 MYL    Mylan NV   United ~        0.245       0.418     0.088 0.161
10 MYL    Mylan NV   United ~        0.244       0.428     0.094 0.163
11 MYL    Mylan NV   United ~        0.228       0.44      0.09  0.153
12 MYL    Mylan NV   United ~        0.242       0.457     0.12  0.169
13 MYL    Mylan NV   United ~        0.243       0.447     0.09  0.133
14 MYL    Mylan NV   United ~        0.19        0.424     0.043 0.052
15 MYL    Mylan NV   United ~        0.272       0.402     0.058 0.121
16 MYL    Mylan NV   United ~        0.258       0.35      0.031 0.074
# ... with 2 more variables: roe <dbl>, year <dbl>

Select columns; ticker, name, and ros

drug_cos %>% 
  select(ticker, name, ros)

# A tibble: 104 x 3
   ticker name             ros
   <chr>  <chr>          <dbl>
 1 ZTS    Zoetis Inc     0.101
 2 ZTS    Zoetis Inc     0.171
 3 ZTS    Zoetis Inc     0.176
 4 ZTS    Zoetis Inc     0.195
 5 ZTS    Zoetis Inc     0.14 
 6 ZTS    Zoetis Inc     0.286
 7 ZTS    Zoetis Inc     0.321
 8 ZTS    Zoetis Inc     0.326
 9 PRGO   PERRIGO Co plc 0.178
10 PRGO   PERRIGO Co plc 0.183
# ... with 94 more rows

Use select to exclude columns; ticker, name, ros.

drug_cos %>% 
  select(-ticker, -name, -ros)

# A tibble: 104 x 6
   location          ebitdamargin grossmargin netmargin   roe  year
   <chr>                    <dbl>       <dbl>     <dbl> <dbl> <dbl>
 1 New Jersey; U.S.A        0.149       0.61      0.058 0.069  2011
 2 New Jersey; U.S.A        0.217       0.64      0.101 0.113  2012
 3 New Jersey; U.S.A        0.222       0.634     0.111 0.612  2013
 4 New Jersey; U.S.A        0.238       0.641     0.122 0.465  2014
 5 New Jersey; U.S.A        0.182       0.635     0.071 0.285  2015
 6 New Jersey; U.S.A        0.335       0.659     0.168 0.587  2016
 7 New Jersey; U.S.A        0.366       0.666     0.163 0.488  2017
 8 New Jersey; U.S.A        0.379       0.672     0.245 0.694  2018
 9 Ireland                  0.216       0.343     0.123 0.248  2011
10 Ireland                  0.226       0.345     0.127 0.236  2012
# ... with 94 more rows

Rename and re-order columns using select() -start with drug_cos THEN -change the location name to headquarter -put columns in order; year, ticker, headquarter, net margin, roe
```
drug_cos %>%
  select(year, ticker, headquarter =location, netmargin, roe)
```

# A tibble: 104 x 5
    year ticker headquarter       netmargin   roe
   <dbl> <chr>  <chr>                 <dbl> <dbl>
 1  2011 ZTS    New Jersey; U.S.A     0.058 0.069
 2  2012 ZTS    New Jersey; U.S.A     0.101 0.113
 3  2013 ZTS    New Jersey; U.S.A     0.111 0.612
 4  2014 ZTS    New Jersey; U.S.A     0.122 0.465
 5  2015 ZTS    New Jersey; U.S.A     0.071 0.285
 6  2016 ZTS    New Jersey; U.S.A     0.168 0.587
 7  2017 ZTS    New Jersey; U.S.A     0.163 0.488
 8  2018 ZTS    New Jersey; U.S.A     0.245 0.694
 9  2011 PRGO   Ireland               0.123 0.248
10  2012 PRGO   Ireland               0.127 0.236
# ... with 94 more rows