# Python: Find the first duplicate element in a given array of integers

## Python: Array Exercise-15 with Solution

Write a Python program to find the first duplicate element in a given array of integers. Return -1 if there are no such elements.

**Sample Solution**:

**Python Code :**

```
def find_first_duplicate(nums):
num_set = set()
no_duplicate = -1
for i in range(len(nums)):
if nums[i] in num_set:
return nums[i]
else:
num_set.add(nums[i])
return no_duplicate
print(find_first_duplicate([1, 2, 3, 4, 4, 5]))
print(find_first_duplicate([1, 2, 3, 4]))
print(find_first_duplicate([1, 1, 2, 3, 3, 2, 2]))
```

Sample Output:

4 -1 1

**Python Code Editor:**

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**Previous:** Write a Python program to find if a given array of integers contains any duplicate element. Return true if any value appears at least twice in the said array and return false if every element is distinct.

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