On this page we'll keep track of the Python types, functions, and operators that we've covered in class. You can also review the online Python References for more complete coverage, BUT NOTE there is far more detail on the Python documenation than we will cover!
The reference page below is all you should need to complete the exam.
| Mathematical Operators | Symbol | Meaning | Example |
|---|---|---|
| + | addition | 4 + 5 = 9 |
| - | subtraction | 9 - 5 = 4 |
| * | multiplication | 3*5 = 15 |
| / | division | 6/4 = 1.5 |
| // | floor division | 6//4 = 1 |
| % | mod/remainder | 5 % 3 = 2 |
| ** | exponentiation | 3**2 = 9, 2**3 = 8 |
| String Operators | + | concatenation | "ab"+"cd"="abcd" |
| * | repeat | "xo"*3 = "xoxoxo" |
| Comparison Operators | == | is equal to | 3 == 3 is True |
| != | is not equal to | 3 != 3 is False |
| >= | is greater than or equal to | 4 >= 3 is True |
| <= | is less than or equal to | 4 <= 3 is False |
| > | is strictly greater than | 4 > 3 is True |
| < | is strictly less than | 3 < 3 is False |
| Boolean Operators | ||
x=5 | not | flips/negates the value of a bool | (not x == 5) is False |
| and | returns True only if both parts of it are True | (x > 3 and x < 7) is True (x > 3 and x > 7) is False |
| or | returns True if at least one part of it is True | (x < 3 or x > 7) is False (x < 3 or x < 7) is True |
| Type Conversion Functions | ||
| int(x) | turn x into an integer value | int("123") == 123 |
| int can fail, e.g., int("abc") raises an error | ||
| float(x) | turn x into an float value | float("2.46") == 2.46 |
| float can fail, e.g., float("abc") raises an error | ||
| str(x) | turn x into a string value | str(432) == "432" |
| type(x) | the type of x | type(1) ==
int type(1.2) == float |
| String Functions | ||
s="colorful" | Name | Returns | Example |
| .split() | list of "words" in s separated by whitespace | "big bad dog".split() == ["big","bad", "dog"] |
| .split(",") | list of "items " in s that are separated
by a comma
In general can split on any string, not just a comma, e.g., s.split(":") will split on a colon and s.split("gat") will split on the string "gat". | "this,old,man".split(",") == ["this", "old", "man"] |
| Miscellaneous Functions | ||
| len(x) | length of sequence x, e.g., String/List | len("duke") == 4 |
| Math Functions (import math) | ||
| math.pi | 3.1415926535897931 | |
| math.sqrt(num) | returns square root of num as float | math.sqrt(9) == 3.0 |
| Random Functions (import random) | ||
| random.randint(start, end) | Returns a random integer between start and end inclusive. So random.randint(0,2) can return 0, 1, or 2. | |