Introduction to Python: Glossary

Basic data types in Python include integers, strings, and floating-point numbers.

Use variable = value to assign a value to a variable in order to record it in memory.

Variables are created on demand whenever a value is assigned to them.

Use print(something) to display the value of something.

Built-in functions are always available to use.

Import a library into a program using import libraryname.

Use the numpy library to work with arrays in Python.

The expression array.shape gives the shape of an array.

Use array[x, y] to select a single element from a 2D array.

Array indices start at 0, not 1.

Use low:high to specify a slice that includes the indices from low to high-1.

Use # some kind of explanation to add comments to programs.

Use numpy.mean(array), numpy.max(array), and numpy.min(array) to calculate simple statistics.

Use numpy.mean(array, axis=0) or numpy.mean(array, axis=1) to calculate statistics across the specified axis.

Use the pyplot module from the matplotlib library for creating simple visualizations.

[value1, value2, value3, ...] creates a list.

Lists can contain any Python object, including lists (i.e., list of lists).

Lists are indexed and sliced with square brackets (e.g., list[0] and list[2:9]), in the same way as strings and arrays.

Lists are mutable (i.e., their values can be changed in place).

Strings are immutable (i.e., the characters in them cannot be changed).

Use for variable in sequence to process the elements of a sequence one at a time.

The body of a for loop must be indented.

Use len(thing) to determine the length of something that contains other values.

Use glob.glob(pattern) to create a list of files whose names match a pattern.

Use * in a pattern to match zero or more characters, and ? to match any single character.