### Table Functions and Methods

 Name Chapter Description `Table` 5 Create an empty table, usually to extend with data `Table.read_table` 5 Create a table from a data file `with_columns` 5 Create a copy of a table with more columns `column` 5 Create an array containing the elements of a column `num_rows` 5 Compute the number of rows in a table `num_columns` 5 Compute the number of columns in a table `labels` 5 Lists the column labels in a table `select` 5 Create a copy of a table with only some of the columns `drop` 5 Create a copy of a table without some of the columns `relabel` 5 Modifies the existing table in place, changing the column heading in the first argument to the second `relabeled` 5 Returns a new table with the column heading in the first argument changed to the second `sort` 5.2 Create a copy of a table sorted by the values in a column. Defaults to ascending order unless “descending = True” is included `where` 5.3 Create a copy of a table with only the rows that match some predicate `take` 5.3 Create a copy of the table with only the rows whose indices are in the given array `barh` 6.1 Draws a bar chart of the frequencies of a categorical distribution `histogram` 6.2 Draws a histogram of a numerical distribution `apply` 7.1 Returns an array of a a function applied to some row in a table `group` 7.2 Create a copy of the table with all rows with the same values in a certain column aggregated into one row in the new table `groups` 7.3 Create a copy of the table with all rows with the same value in a certain array of columns aggregated into one row in the new table `pivot` 7.3 Create a copy of the table with a column for each element in the first argument and a row for each element in the second argument and aggregates values `join` 7.4 Create a copy of the table that is the result of joining the columns of two tables, with a row for each shared value in the two tables `sample` 9 Draws some number of rows at random from a table. By default, with replacement. `proportion_from_distribution` 10.1 Returns a new table with an additional column corresponding to proportions from a random sample of some size of the proportions in a column.

### Array Functions and Methods

 Name Chapter Description `max` 3.3 Returns the maximum value of an array `min` 3.3 Returns the minimum value of an array `sum` 3.3 Returns the sum of the values in an array `len` 3.3 Returns the length (number of elements) of an array `make_array` 4.4 Makes a numpy array with the values passed in `np.average` 4.4 Returns the mean value of an array `np.std` 12.2 Returns the standard deviation of an array of numbers `np.diff` 4.4 Returns a new array of size len(arr)-1 with elements equal to the difference between adjacent elements `np.sqrt` 4.4 Returns an array with the square root of each element `np.arange` 4.5 Returns an array of an end-exclusive range of variable step size `arr.item` 4.6 Returns the i-th item in an array (remember Python indices start at 0!) `np.random.choice` 8 Picks one (by default) or some number 'n' of items from an array at random. By default, with replacement. `np.count_nonzero` 8 Returns the number of non-zero (or True) elements in an array. `np.append` 8.2 Returns a copy of the input array with some item (must be the same type as the other entries in the array) appended to the end. `percentile` 11.1 Returns the corresponding percentile of an array.