FAQs
Selection of data frame elements | R? ›
Similar to vectors and matrices, you select elements from a data frame with the help of square brackets [ ] . By using a comma, you can indicate what to select from the rows and the columns respectively. For example: my_df[1,2] selects the value at the first row and second column in my_df .
How do I select part of a Dataframe in R? ›The most general way to subset a data frame by rows and/or columns is the base R Extract[] function, indicated by matched square brackets instead of the usual matched parentheses. For a data frame named d the general format is d[rows, columms] .
How do you select specific values in a Dataframe in R? ›We can select column values in R simply by using the “dataframe name + $ + column name “. In the example below we will be selecting the Species column of the dataset. We can select the column using the indexing method as well and get the exact same output.
How do you select certain variables in R? ›To limit your dataset to a subset of variables in base R, use brackets [ ] or subset() . In tidyverse , use select() . As with subset() , you name the variables you want to keep, without quotes, or precede with a minus sign the names of variables you want to drop.
How do you select specific Dataframe columns in R? ›Selecting a Specific Column [Shortcut]
To select a specific column, you can also type in the name of the dataframe, followed by a $ , and then the name of the column you are looking to select.
Similar to vectors and matrices, you select elements from a data frame with the help of square brackets [ ] . By using a comma, you can indicate what to select from the rows and the columns respectively. For example: my_df[1,2] selects the value at the first row and second column in my_df .
How do you select part of a DataFrame? ›When selecting subsets of data, square brackets [] are used. Inside these brackets, you can use a single column/row label, a list of column/row labels, a slice of labels, a conditional expression or a colon. Select specific rows and/or columns using loc when using the row and column names.
How to extract specific values from DataFrame in R? ›Extract data frame cell value
- Extract value of a single cell: df_name[x, y] , where x is the row number and y is the column number of a data frame called df_name .
- Extract the entire row: df_name[x, ] , where x is the row number. ...
- Extract the entire column: df_name[, y] where y is the column number.
In this tutorial, we introduce how to filter a data frame rows using the dplyr package:
- Filter rows by logical criteria: my_data %>% filter(Sepal. ...
- Select n random rows: my_data %>% sample_n(10)
- Select a random fraction of rows: my_data %>% sample_frac(10)
- Select top n rows by values: my_data %>% top_n(10, Sepal.
R Data Frames
- Data Frames. Data Frames are data displayed in a format as a table. ...
- Access Items. We can use single brackets [ ] , double brackets [[ ]] or $ to access columns from a data frame: ...
- Add Rows. Use the rbind() function to add new rows in a Data Frame: ...
- Add Columns. ...
- Remove Rows and Columns. ...
- Data Frame Length.
How do I cut a DataFrame in half in R? ›
Use the split() function in R to split a vector or data frame. Use the unsplit() method to retrieve the split vector or data frame.