Midterm 1 Study Guide

abs()

returns the absolute value of the function in the parentheses

round(x,y)

rounds x to y digits to the right of the decimal. y can be negative to round to the 10s/100s place, and if left blank rounds to the nearest integer. If 0.5, rounds to the nearest even integer.

table.show(x)

shows x number of rows of the table as a picture(can’t do functions on it)

table.select(x)

creates a new table with only the ‘x’ columns

table.drop(x)

creates a new table without the ‘x’ columns

table.where(x, y)

creates a new table with only the values in column x that meet condition y

table.sort(x)

sorts the table by column x, from least to greatest. can put “, descending = True” after x to sort the table from greatest to least

When is a float returned as an answer

when one of the variables is a float or division is used.

‘string’ + ‘string’

‘stringstring’

‘string’ * 3

‘stringstringstring’

int(‘x’) & Condition

returns x as an integer

X can’t have decimals

float(‘x’)

x.0

type(x)

returns the type of value that x is

make_array('x’, ‘y’, ‘z’)

makes an array with elements x, y, z

array *, /, -, +, ** x

applies the function to each individual value of the array

len(x)

returns the # of columns in a table or the # of items in an array

array.item(x)

returns the item in the array(starts at item 0, can be negative)

np.arange(x) OR np.arange(y,z)

gives an array with x # of values in it

OR

gives an array starting at y and ending at the last value less than z

Table.()

creates an empty column

.with_column(x,y)

adds a column with title ‘x’ and array ‘y’ as its values

.num_rows OR .num_columns

gives the number of rows or columns in a table

.labels

gives the names of the columns of a table

.set_format(x, PercentFormatter)

Makes a decimal into a percent

table.plot(x,y)

makes a line graph with axes “x” and “y”

table.relabeled(x,y)

x is either a number(starts at 0, goes from left to right) or the name of the column. y is the new label

plots.ylim(x,y) OR plots.xlim(x,y)

sets the lower bound of a line plot axis at x and the upper bound at y

table.scatter(x,y, group = z)

scatterplot with “x” on the horizontal axis and “y” on the vertical axis, and with different colored dots based on grouping z.

table.take(x) or table.take(np.arange(y))

takes the (x-1)th value of a table and makes it a new table

makes a new table with the top y values from the table

table.barh(‘x’, ‘y’)

creates a bar chart with ‘x’ as the horizontal axis and ‘y’ as the vertical axis

table.group(‘x’)

creates a new table with columns “x” and “count”

table.bin(x, bins = np.arange(y,z,a))

arranges variable x into bins ranging from y to z spaced “a” apart

table.hist(x, bins = y, (normed = False))

creates a histogram of variable x with bins y; it has percent per unit x as the default y variable

if normed = False, uses Count as the y-axis variable

plots.plot(x,y)

creates a graph of the given x values and the given y values. can use arrays for both to make line segments.

plots.title(x)

titles the plot “x”

def function(x):

return (function 2)

defines function of x as function 2

NOTE: variables defined in the function cannot be called later on

string.count(x)

count the number of “x” in the string

table.apply(x,y)

applies function x to column y

np.unique(x)

gives the unique values in array x

plots.axvline(x)

puts a vertical line at a specified x value on a plot

table.group(x,np.y)

creates a table grouped by value x, with the np.y function applied to the values it displays

table.pivot(x,y,z, (np.a))

creates a 2 way table with x as the column grouper, y as the row grouper, z as the measured variable, and np.a as the function applied to the values.

table1.join(x,y,z)

adds a new column to table1, matching the values in column x to the values in column z from table y. Unmatched values will not display in the table.

Table().read_table(x)

makes a table with the values read from table x.

np.diff(array))

returns another array with n-1 values about the difference in the values (n2-n1, n3-n2, etc.)

are.between(x,y)

are.between_or_equal_to(x,y)

are.strictly_between(x,y)

greater than or equal to x, and less than y

greater than or equal to x, and less than or equal to y

greater than x and less than y

are.contained_in(A)

is a substring of A(string) or element of A(array)

are.containing(S)

contain the string s