Check if multiple variables have the same value
Question:
I have a set of three variables x, y, z and I want to check if they all share the same value. In my case, the value will either be 1 or 0, but I only need to know if they are all the same. Currently I’m using
if 1 == x and 1 == y and 1 == z:
sameness = True
Looking for the answer I’ve found:
if 1 in {x, y, z}:
However, this operates as
if 1 == x or 1 == y or 1 == z:
atleastOneMatch = True
Is it possible to check if 1 is in each: x, y, and z?
Better yet, is there a more concise way of checking simply if x, y, and z are the same value?
(If it matters, I use Python 3.)
Answers:
How about this?
x == y == z == 1
Another way:
sameness = all(e == 1 for e in [x, y, z])
If you have an arbitrary sequence, use the all() function with a generator expression:
values = [x, y, z] # can contain any number of values
if all(v == 1 for v in values):
otherwise, just use == on all three variables:
if x == y == z == 1:
If you only needed to know if they are all the same value (regardless of what value that is), use:
if all(v == values[0] for v in values):
or
if x == y == z:
To check if they are all the same (either 1 or 2):
sameness = (x == y == z)
The parentheses are optional, but I find it improves readability
You could use something similar to what you have:
sameness = (len({x, y, z}) == 1)
This allows for any number of variables. For example:
variables = {x, y, z, a, b, ...}
sameness = (len(variables) == 1)
Note: Creating a set means that each variable needs to be hashed and the hashed values need to be stored, but all() with a generator expression is short-circuiting and keeps track of only two values at a time. Therefore, besides its readability, the generator expression is more efficient.
In my case, the value will either by 1 or 2, but I only need to know if they are all the same
Is it possible to check if 1 is in each: x, y, and z?
Better yet, is there a more concise way of checking simply if x, y, and z are the same value?
Sure:
x == y == z
which is equivalent to
(x == y) and (y == z)
If you have an arbitrary (nonzero) number of values to compare:
all(values[0] == v for v in values[1:])
[x,y,z].count(1)
will count how many variables have 1 as value
Below all() and any() functions in python can server the purpose.
all() act as "AND": if all the values in any ittertable object is equal to given condition value, then Return True else return False.
Examples
assert all(b == True for b in [True,True,True,True]) == True
assert all(b == True for b in [False,True,True,True]) == False
any() act as "OR": if any one value in any ittertable object is equal to given condition value, then Return True else return False.
Examples
assert any(b == True for b in [False,False,False,True]) == True
assert any(b == True for b in [False,False,False,False]) == False
If you had more variables, this way might be most concise:
{x} == {y, z}
(Not as fast as x == y == z, but the question asked for concise, not for fast.)
I have a set of three variables x, y, z and I want to check if they all share the same value. In my case, the value will either be 1 or 0, but I only need to know if they are all the same. Currently I’m using
if 1 == x and 1 == y and 1 == z:
sameness = True
Looking for the answer I’ve found:
if 1 in {x, y, z}:
However, this operates as
if 1 == x or 1 == y or 1 == z:
atleastOneMatch = True
Is it possible to check if 1 is in each: x, y, and z?
Better yet, is there a more concise way of checking simply if x, y, and z are the same value?
(If it matters, I use Python 3.)
How about this?
x == y == z == 1
Another way:
sameness = all(e == 1 for e in [x, y, z])
If you have an arbitrary sequence, use the all() function with a generator expression:
values = [x, y, z] # can contain any number of values
if all(v == 1 for v in values):
otherwise, just use == on all three variables:
if x == y == z == 1:
If you only needed to know if they are all the same value (regardless of what value that is), use:
if all(v == values[0] for v in values):
or
if x == y == z:
To check if they are all the same (either 1 or 2):
sameness = (x == y == z)
The parentheses are optional, but I find it improves readability
You could use something similar to what you have:
sameness = (len({x, y, z}) == 1)
This allows for any number of variables. For example:
variables = {x, y, z, a, b, ...}
sameness = (len(variables) == 1)
Note: Creating a set means that each variable needs to be hashed and the hashed values need to be stored, but all() with a generator expression is short-circuiting and keeps track of only two values at a time. Therefore, besides its readability, the generator expression is more efficient.
In my case, the value will either by 1 or 2, but I only need to know if they are all the same
Is it possible to check if 1 is in each: x, y, and z?
Better yet, is there a more concise way of checking simply if x, y, and z are the same value?
Sure:
x == y == z
which is equivalent to
(x == y) and (y == z)
If you have an arbitrary (nonzero) number of values to compare:
all(values[0] == v for v in values[1:])
[x,y,z].count(1)
will count how many variables have 1 as value
Below all() and any() functions in python can server the purpose.
all() act as "AND": if all the values in any ittertable object is equal to given condition value, then Return True else return False.
Examples
assert all(b == True for b in [True,True,True,True]) == True
assert all(b == True for b in [False,True,True,True]) == False
any() act as "OR": if any one value in any ittertable object is equal to given condition value, then Return True else return False.
Examples
assert any(b == True for b in [False,False,False,True]) == True
assert any(b == True for b in [False,False,False,False]) == False
If you had more variables, this way might be most concise:
{x} == {y, z}
(Not as fast as x == y == z, but the question asked for concise, not for fast.)