Python 2 includes a cmp
function which allows you to determine if one object is less than, equal to, or greater than another object. This function can be used to pick a choice out of a list based on one of those three options.
Suppose you need to print 'greater than'
if x > y
, 'less than'
if x < y
and 'equal'
if x == y
.
['equal', 'greater than', 'less than', ][cmp(x,y)]
# x,y = 1,1 output: 'equal'
# x,y = 1,2 output: 'less than'
# x,y = 2,1 output: 'greater than'
cmp(x,y)
returns the following values
| Comparison | Result |
|————|––––|
| x \\< y | -1 |
| x == y | 0 |
| x > y | 1 |
This function is removed on Python 3. You can use the [cmp_to_key(func)](<https://docs.python.org/3/library/functools.html#functools.cmp_to_key>)
helper function located in [functools](<http://stackoverflow.com/documentation/python/2492/functools#t=201608152305056538775>)
in Python 3 to convert old comparison functions to key functions.