## Python program to check if a series is Arithmetic progression or not:

In this post, we will learn how to check if a *series* is *Arithmetic progression* series or not. The program will take one *series* of numbers and print one message that this is an *Arithmetic progression* or not.

For example, *1, 3, 5, 7, 9, 11* is an *Arithmetic progression*, but *2, 4, 7, 8* is not.

## Algorithm to check for AP:

For an *Arithmetic progression* or *AP*, each numbers are separated by a *constant* value. This value is called *common difference*.

So, we can check if the *common difference* or if the *difference* between two numbers are equal or not for all values.

We can follow these steps to check if a series is an *Arithmetic progression* or not:

- Find the difference between the
*first*and the*second*number and store it in a variable. -
Start from the

*third*number and for each number,- Check if the difference between
*this number*and its*previous*number is equal to the difference we checked in the*first*step. - If the difference is not
*equal*, this is not an*AP*.. - If the difference is
*equal*, move to the next number.

- Check if the difference between
- If all differences are
*equal*, this is an*Arithmetic progression*.

### Python program:

Below is the complete python program:

```
def check_arithmetic_progression(arr):
diff = arr[1] - arr[0]
n = len(arr)
for i in range(2, n):
if arr[i] - arr[i - 1] != diff:
return False
return True
print(check_arithmetic_progression([1, 3, 5, 7, 9, 11]))
print(check_arithmetic_progression([1, 3, 5, 7, 9, 11, 12]))
print(check_arithmetic_progression([1, 3, 5, 7, 9, 11, 13, 15]))
print(check_arithmetic_progression([5, 10, 11, 12]))
```

Here,

*check*method is used to check if an*arithmetic*progression*array*is an*Arithmetic progression*or not.- It calculates the difference between the
*second*and the*first*element and store that value in*diff*. This is the*common difference*that we want for all places in the*series*. - The
*for*loop starts from the index*2*, or from the*third*element of the array to the*end*of the array. -
For each number, it calculates the

*difference*or*common difference*by subtracting the previous number from the current number.- It calculates if the
*difference*is equal to the calculated*diff*or not. If*not*, it returns*False*.

- It calculates if the
- Once the
*for loop*ends, it returns*True*, because all numbers have equal*common difference*.

### Output:

If you run this program, it will print the below output:

```
True
False
True
False
```

### You might also like:

- Python program to find the power of a number using Anonymous function
- How to sort a list of tuple in python
- Python string hexdigits explanation with example
- How to check if a tuple contains an element in Python
- Print the even and odd index characters of a string in python
- Python program to convert a tuple of strings to string
- Python program to print Arithmetic progression series