📋 Python Arrays – Copy, Reverse, Sort, and Join Arrays
🧲 Introduction – Managing Array Data Efficiently
Arrays in Python are used for storing fixed-type values efficiently, particularly numeric data. Once you’ve created and modified an array, you often need to copy, reverse, sort, or combine them.
This guide shows how to perform these essential operations using Python’s built-in array module.
🎯 In this guide, you’ll learn how to:
- Copy an array (shallow copy)
- Reverse an array using slicing and
.reverse() - Sort an array manually
- Join arrays using concatenation
🔧 Importing the Array Module
from array import array
✅ The array module must be imported before using array objects.
📄 1. Copying a Python Array
✅ Using array.copy() (Python 3.3+)
nums = array('i', [10, 20, 30])
copy_nums = nums.copy()
copy_nums.append(40)
print(nums) # array('i', [10, 20, 30])
print(copy_nums) # array('i', [10, 20, 30, 40])
✅ Explanation:
.copy()creates a shallow copy of the array.- Modifying the copied array does not affect the original.
🔄 2. Reversing a Python Array
✅ Method 1: Using .reverse()
nums.reverse()
print(nums) # Reversed in-place
✅ Modifies the original array.
✅ Method 2: Using Slicing
reversed_array = nums[::-1]
print(reversed_array)
✅ Returns a new reversed array (as a list-like structure).
🔃 3. Sorting a Python Array
⚠️ Python’s array module does not have a built-in .sort() method.
✅ Solution: Convert to List → Sort → Convert Back
sorted_array = array('i', sorted(nums))
print(sorted_array)
✅ Explanation:
sorted()returns a sorted list.- Convert it back to an array using the same type code.
🔗 4. Joining Arrays (Concatenation)
a1 = array('i', [1, 2, 3])
a2 = array('i', [4, 5])
combined = a1 + a2
print(combined)
✅ Explanation:
- Arrays of the same type code can be joined using
+. - Output:
array('i', [1, 2, 3, 4, 5])
💡 Best Practices
- ✅ Always copy arrays before modifying if you need to retain the original.
- ✅ Use
.reverse()for in-place changes; use slicing to keep original intact. - ✅ For sorting, convert to list and back using
array(typecode, sorted(arr)). - ✅ Ensure type codes match when joining arrays.
📌 Summary – Recap & Next Steps
Arrays in Python provide a structured way to handle numeric data. Learning to copy, reverse, sort, and join them helps manage data more flexibly and efficiently in memory-sensitive or performance-intensive applications.
🔍 Key Takeaways:
- ✅ Use
.copy()for shallow copies. - ✅ Reverse with
.reverse()or slicing. - ✅ Sort arrays via list conversion and
sorted(). - ✅ Join arrays using
+if they share the same type code.
⚙️ Real-World Relevance:
These techniques are widely used in signal processing, data aggregation, sensor arrays, and scientific simulations.
❓ FAQ Section – Copy, Reverse, Sort, Join Arrays
❓ How do I copy a Python array safely?
✅ Use:
arr.copy()❓ Can I reverse an array without modifying the original?
✅ Yes. Use slicing:
reversed_arr = arr[::-1]❓ How can I sort a Python array?
✅ Convert it to a list, use sorted(), then convert back:
sorted_array = array('i', sorted(arr))❓ Can I join two arrays with different type codes?
❌ No. You can only join arrays that share the same type code.
❓ Is there a .sort() method for Python arrays?
❌ No. Use sorted() with list conversion for sorting.
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