Specialization: Data Science by Johns Hopkins University.Course: Machine Learning: Master the Fundamentals by Standford.The simplified syntax is as follow: gather_(data, key_col, value_col, gather_cols)Ĭoursera - Online Courses and Specialization Data science You should use the function gather_() which takes character vectors, containing column names, instead of unquoted column names How to use gather() programmatically inside an R function?. The remaining state column is duplicated. My_data2 state Rape arrest_attribute arrest_estimate Gather all variables between Murder and UrbanPop.Note that, the two columns Murder and Assault have been collapsed and the remaining columns (state, UrbanPop and Rape) have been duplicated. My_data2 state UrbanPop Rape arrest_attribute arrest_estimate Their values have been put into a value column (here “arrest_estimate”). Note that, all column names (except state) have been collapsed into a single key column (here “arrest_attribute”). My_data2 state arrest_attribute arrest_estimate Gather all columns except the column state.if you want to exclude a column name y use -y.if you want to select all variables between a and e, use a:e.…: Specification of columns to gather.key, value: Names of key and value columns to create in output.Sometimes you need to go back to fix something in the previous steps. The current step will shed new light on what to do next. The analytical process is aggregated instead of independent steps. It makes us wonder what is the average expense each time, so you have a better idea about the price range of the group. You may notice that Style group purchase more frequently online ( online_trans) but the expense ( online_exp) is not higher. They are very likely to be digital natives and prefer online shopping. Style: They are young people with average age 24. More than half of them don’t own a house (0.66). The percentages of male and female are similar. They are not way different with Conspicuous regarding age. It is the only group that is less likely to buy online. They are less likely to purchase online ( store_trans = 6 while online_trans = 3). Price: They are older people with average age 60. 1/3 of them are female, and 2/3 are male. It is a group of middle-age wealthy people. There is a lot of information you can extract from those simple averages.Ĭonspicuous: average age is about 40. online_trans: average times of online transactions.store_trans: average times of transactions in the store.HouseYes: percentage of people who own a house.In the end, we calculate the following for each segment: The rest of the command above is similar. Store the result in a new variable named Age.Round the result to the specified number of decimal places.Calculate the mean of column age ignoring missing value for each customer segment.For example, Age = round(mean(na.omit(age)),0) tell R the following things: Then list the exact actions inside summarise(). The third argument summarise tells R the manipulation(s) to do. Here we only summarize data by one categorical variable, but you can group by multiple variables, such as group_by(segment, house). The second line group_by(segment) tells R that in the following steps you want to summarise by variable segment. Now, let’s look at the code in more details. 14.1 Customer Data for Clothing Companyĭat_summary % dplyr :: group_by(segment) %>% dplyr :: summarise( Age = round( mean( na.omit(age)), 0), FemalePct = round( mean(gender = "Female"), 2), HouseYes = round( mean(house = "Yes"), 2), store_exp = round( mean( na.omit(store_exp), trim = 0.1), 0), online_exp = round( mean(online_exp), 0), store_trans = round( mean(store_trans), 1), online_trans = round( mean(online_trans), 1)) # transpose the data frame for showing purpose # due to the limit of output width cnames % ame() names(tdat_summary) 12.1.1 Logistic Regression as Neural Network.11.4 Regression and Decision Tree Basic.10.4 Penalized Generalized Linear Model.9.2 Principal Component Regression and Partial Least Square.9.1.2 Diagnostics for Linear Regression.6.1.2 apply(), lapply() and sapply() in base R.5.2.1 Impute missing values with median/mode.4.3.1 Open Account and Create a Cluster.3.1 Customer Data for a Clothing Company.2.5.4 Model Implementation and Post Production Stage.2.4.4 Model Implementation and Post Production Stage.2.4.2 Problem Formulation and Project Planning Stage.2.1 Comparison between Statistician and Data Scientist.1.3 What Kind of Questions Can Data Science Solve?.
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