 # 25 Interesting Python Codes to Solve Complex Tasks

## Part 1: A list of Python codes for solving complex tasks. In the process of learning Python, you will always find that Python can easily solve many problems. Some complex tasks can even be done with a single line of Python code.

Here are 25 interesting Python codes, all of which are practical. I hope you can find they are useful.

### 1. Letter Anagram

If two words contain the same letters and are in a different order, they are called anagrams. For example, “silent” and “listen” are letter anagrams, while “apple” and “aplee” are not.

``````from collections import Counter

s1 = 'below'
s2 = 'elbow'

print('anagram') if Counter(s1) == Counter(s2) else print('not an anagram')
``````

### 2. Binary to Decimal

``````decimal = int('1010', 2)
print(decimal) #10
``````

### 3. Convert String to Lowercase

``````print("Hi my name is Tony Xu".lower())
# 'hi my name is tony xu'

print("Hi my name is Tony Xu".casefold())
# 'hi my name is tony xu'
``````

### 4. Convert String to Uppercase

``````print("hi my name is Tony Xu".upper())
# 'HI MY NAME IS Tony Xu'
``````

### 5. Convert String to Bytes

``````print("convert string to bytes using encode method".encode())
# b'convert string to bytes using encode method'
``````

### 6. Copy File

``````import shutil

shutil.copyfile('source.txt', 'dest.txt')
``````

### 7. Quick Sort

``````qsort = lambda l: l if len(l) <= 1 else qsort([x for x in l[1:] if x < l]) + [l] + qsort([x for x in l[1:] if x >= l])

print(qsort([17, 29, 11, 97, 103, 5]))
# [5, 11, 17, 29, 97, 103]
``````

### 8. Sum of N Numbers

``````n = 10

print((lambda x: (x*(x+1))/2)(n)
# 55
``````

### 9. Switch the Value of Two Variables

``````a, b = b, a
``````

### 10. Fibonacci

``````fib = lambda x: x if x<=1 else fib(x-1) + fib(x-2)

print(fib(20))
# 6765
``````

### 11. Combine Nested Lists into One List

``````main_list = [[0, 1, 2], [11, 12, 13], [52, 53, 54]]

result = [item for sublist in main_list for item in sublist]
print(result)

>
[0, 1, 2, 11, 12, 13, 52, 53, 54]
``````

### 12. Run an HTTP Server

``````python3 -m http.server 8000
python2 -m SimpleHTTPServer
``````

### 13. Reverse a List

``````numbers = [0, 1, 2, 11, 12, 13, 52, 53, 54]

print(numbers[::-1])
# [54, 53, 52, 13, 12, 11, 2, 1, 0]
``````

### 14. Factorial

``````import math

fact_5 = math.factorial(5)
print(fact_5)
# 120
``````

### 15. Use for and if in List Comprehensions

``````even_list = [number for number in [1, 2, 3, 4] if number % 2 == 0]

print(even_list)
# [2, 4]
``````

### 16. The Longest String in List

``````words = ['This', 'is', 'a', 'list', 'of', 'words']

result = max(words, key=len)
print(result)
# 'words'
``````

### 17. List Comprehension

``````li = [num for num in range(0, 10)]

print(li)
# [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
``````

### 18. Set Comprehension

``````num_set = {num for num in range(0, 10)}

print(num_set)
# {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
``````

### 19. Dict Comprehension

``````dict_numbers = {x: x*x for x in range(1, 5)}

print(dict_numbers)
# {1: 1, 2: 4, 3: 9, 4: 16}
``````

### 21. Print with if and else

``````print("even") if 4 % 2==0 else print("odd")
``````

### 22. Infinite Loop

``````while 1:0
``````

### 23. Check Data Type

``````print(isinstance(2, int))
# True

print(isinstance("allwin", str))
# True

print(isinstance([3, 4, 1997], list))
# True
``````

### 24. Print to File

``````print("Hello, World!", file=open('file.txt', 'w'))
``````

### 25. Frequency of a Character in a String

``````print("umbrella".count('l'))
# 2
``````

And there you have it. Thank you for reading.