How to test multiple variables for equality against a single value?

Python If Statement Comparison Match Boolean Logic

If you want to compare multiple variables to a single value in Python and perform specific actions based on the comparison results, there are several approaches you can take. In this article, we will explore three different methods to solve this problem and provide examples for each method.

Method 1: Using if statements

The most straightforward way to compare multiple variables to a single value is by using if statements. You can create separate if statements for each comparison and append the corresponding string to a list if the condition is met. Here's how you can do it:

mylist = []
x = 0
y = 1
z = 3

if x == 0:
    mylist.append("c")
if y == 0:
    mylist.append("c")
if z == 0:
    mylist.append("c")

if x == 1:
    mylist.append("d")
if y == 1:
    mylist.append("d")
if z == 1:
    mylist.append("d")

if x == 2:
    mylist.append("e")
if y == 2:
    mylist.append("e")
if z == 2:
    mylist.append("e")

if x == 3:
    mylist.append("f")
if y == 3:
    mylist.append("f")
if z == 3:
    mylist.append("f")

print(mylist)  # Output: ["c", "d", "f"]

In this example, we compare each variable (x, y, and z) against the desired value using separate if statements. If the condition evaluates to true, we append the corresponding string to the mylist list. As a result, the final output will be ["c", "d", "f"].

Method 2: Using a dictionary

If you have a large number of variables to compare or if you want a more concise approach, you can use a dictionary to map the desired value to the corresponding string. Here's an example:

mylist = []
x = 0
y = 1
z = 3
mapping = {0: "c", 1: "d", 2: "e", 3: "f"}

for variable in [x, y, z]:
    if variable in mapping:
        mylist.append(mapping[variable])

print(mylist)  # Output: ["c", "d", "f"]

In this example, we define a dictionary called mapping that maps each desired value to its corresponding string. We then iterate over the list of variables (x, y, and z) using a for loop. For each variable, we check if it exists as a key in the mapping dictionary. If it does, we append the corresponding value to the mylist list. As a result, the final output will be ["c", "d", "f"].

Method 3: Using list comprehension

List comprehension is a powerful feature in Python that allows you to create new lists based on existing lists or other iterables. It can also be used to solve our problem of comparing multiple variables to a single value. Here's an example:

x = 0
y = 1
z = 3
mapping = {0: "c", 1: "d", 2: "e", 3: "f"}

mylist = [mapping[variable] for variable in [x, y, z] if variable in mapping]

print(mylist)  # Output: ["c", "d", "f"]

In this example, we use list comprehension to create a new list called mylist. We iterate over the list of variables (x, y, and z) and check if each variable exists as a key in the mapping dictionary. If it does, we append the corresponding value to the mylist list. As a result, the final output will be ["c", "d", "f"].

Conclusion

There are multiple ways to compare multiple variables to a single value in Python and perform specific actions based on the comparison results. You can use if statements, dictionaries, or list comprehension to achieve this goal. Choose the method that suits your specific needs and coding style.

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