Python >> Tips and Tricks 5

# Read file
with open(r"D:\test\test2.txt", "r") as f:
    content = f.read()
    print(content)

# Write file
with open(r"D:\test\test2.txt", "w") as f:
    f.write("update test22222\nupdate test2222222")

# Decorator
def decorator_function(original_function):
    def wrapper_function():
        print("wrapper executed this before {}".format(original_function.__name__))
        return original_function()
    return wrapper_function

@decorator_function
def display():
    print("display function ran")

display()

# Decorator with arguments

def decorator_function(original_function):
    def wrapper_function(*args, **kwargs):
        print("wrapper executed this before {}".format(original_function.__name__))
        return original_function(*args, **kwargs)
    return wrapper_function

@decorator_function
def display(name):
    print("display function ran with {}".format(name))

display("John")

# Decorator with arguments and return value
def decorator_function(original_function):
    def wrapper_function(*args, **kwargs):
        print("wrapper executed this before {}".format(original_function.__name__))
        return original_function(*args, **kwargs)
    return wrapper_function

@decorator_function
def display(name):
    print("display function ran with {}".format(name))
    return "Hi {}".format(name)

display("John")

# Defaultdict
from collections import defaultdict

d = defaultdict(list)
d["a"].append(1)
d["a"].append(2)
d["b"].append(4)
d["b"].append(5)

print(d)

# Defaultdict
from collections import defaultdict

d = defaultdict(int)
d["a"] += 1
d["a"] += 1
d["b"] += 1
d["c"] += 1

print(d)

# Defaultdict
from collections import defaultdict

d = defaultdict(set)
d["a"].add(1)
d["a"].add(2)
d["b"].add(4)
d["b"].add(5)
d["b"].add(6)

print(d)

# Sort list
l = [2, 9, 1, 4, 10, 6, 5, 7, 8, 3]
l.sort()
print(l)

# Sort list
l = [2, 9, 1, 4, 10, 6, 5, 7, 8, 3]
l2 = sorted(l)
print(l2)

# Sort set
s = {2, 9, 1, 4, 10, 6, 5, 7, 8, 3}

s2 = sorted(s)
print(s2)

# Sort dictionary by key
d = {"c": 1, "b": 2, "a": 3}

d2 = sorted(d.items())
print(d2)

# Sort dictionary by key descending
d = {"c": 1, "b": 2, "a": 3}

d2 = sorted(d.items(), reverse=True)
print(d2)

# Sort dictionary by value
d = {"c": 1, "b": 2, "a": 3}

d2 = sorted(d.items(), key=lambda kv: kv[1])
print(d2)

# Sort dictionary by value descending
d = {"c": 1, "b": 2, "a": 3}

d2 = sorted(d.items(), key=lambda kv: kv[1], reverse=True)
print(d2)

# Use format() method
"{} {} {}".format("a", "b", "c")

# Use f-string
a = "a"
b = "b"
c = "c"

print(f"{a} {b} {c}")

# Use % operator
"%s %s %s" % ("a", "b", "c")