20个提升Python代码质量的私藏方法

with open('example.txt', 'r') as f:
    contents = f.read()
    print(contents)

age = 25

if age >= 18:
   can_vote = "Yes"
else:
   can_vote = "No"

print(f"Can vote: {can_vote}")

Can vote: Yes

age = 25
can_vote = "Yes" if age >= 18 else "No"
print(f"Can vote: {can_vote}")

Can vote: Yes

def my_decorator(func):
    def wrapper():
        print("Errors before Editing.")
        func()
        print("Accuracy after Editing.")
    return wrapper


@my_decorator
def my_function():
    print("Hello, world!")


my_function()

Errors before Editing.
Hello, world!
Accuracy after Editing.

fruits = ['apple', 'banana', 'orange', 'grape']

for index, fruit in enumerate(fruits):
    print(index, fruit)

0 apple
1 banana
2 orange
3 grape

list1 = [1, 2, 3]
list2 = ['a', 'b', 'c']
combined_list = list(zip(list1, list2))
print(combined_list)

[(1, 'a'), (2, 'b'), (3, 'c')]

import getpass

password = getpass.getpass("Enter your password: ")
print("Your password is:", password)

help(range)

...value.
 |  
 |  __len__(self, /)
 |      Return len(self).
 |  
 |  __lt__(self, value, /)
 |      Return self<value.
 |  
 |  __ne__(self, value, /)
 |      Return self!=value.
 |  
 |  __reduce__(...)
 |      Helper for pickle.
 |  
 |  __repr__(self, /)
 |      Return repr(self).
 |  
 |  __reversed__(...)
 |      Return a reverse iterator.
 |  
 |  count(...)
 |      rangeobject.count(value) -> integer -- return number of occurrences of value
 |  
 |  index(...)
 |      rangeobject.index(value) -> integer -- return index of value.
 |      Raise ValueError if the value is not present.
 |  
 |  ----------------------------------------------------------------------
 |  Static methods defined here:
 |  
 |  __new__(*args, **kwargs) from builtins.type
 |      Create and return a new object.  See help(type) for accurate signature.
 |  
 |  ----------------------------------------------------------------------
 |  Data descriptors defined here:
 |  
 |  start
 |  
 |  step
 |  
 |  stop

import math
help(math)

...s to radians.

    remainder(x, y, /)
        Difference between x and the closest integer multiple of y.

        Return x - n*y where n*y is the closest integer multiple of y.
        In the case where x is exactly halfway between two multiples of
        y, the nearest even value of n is used. The result is always exact.

    sin(x, /)
        Return the sine of x (measured in radians).

    sinh(x, /)
        Return the hyperbolic sine of x.

    sqrt(x, /)
        Return the square root of x.

    tan(x, /)
        Return the tangent of x (measured in radians).

    tanh(x, /)
        Return the hyperbolic tangent of x.

    trunc(x, /)
        Truncates the Real x to the nearest Integral toward 0.

        Uses the __trunc__ magic method.

DATA
    e = 2.718281828459045
    inf = inf
    nan = nan
    pi = 3.141592653589793
    tau = 6.283185307179586

FILE
    /usr/local/lib/python3.7/lib-dynload/math.cpython-37m-x86_64-linux-gnu.so

phrase = "Goodbye, world!"
print(phrase[::-1])

"""
!dlrow ,eybdooG
"""

x = 10
y = 5
print(f"Initial: {x, y}")

"""
Initial: (10, 5)
"""

x, y = y, x + 2
print(f"Swapped: {x, y}")

"""
Swapped: (5, 12)
"""

import sys

set_ = {1, 2, 3, 4, 5}
list_ = [1, 2, 3, 4, 5]

print(f"Set size: {sys.getsizeof(set_)} bytes")
print(f"List size: {sys.getsizeof(list_)} bytes")

"""
Set size: 232 bytes
List size: 144 bytes
"""

a = [x * 2 for x in range(10)]
b = (x * 2 for x in range(10))

print(a)
print(b)

"""
[0, 2, 4, 6, 8, 10, 12, 14, 16, 18]
<generator object <genexpr> at 0x7f61f8808b50>
"""

original = [1, 2, 3, 4, 5]
alias = original

# Modify alias
alias[4] = 7

print(id(original))
print(id(alias))
print(original)  # Changes reflect in the original list

"""
140279273485184
140279273485184
[1, 2, 3, 4, 7]
"""

empty_list = []
print(not empty_list)

"""
True
"""

name = "Alice"
age = 25

print(f"Hello, I'm {name} and I'm {age} years old!")

"""
Hello, I'm Alice and I'm 25 years old!
"""

languages = ["English", "French", "Spanish", "German", "Twi"]
for language in languages:
    print(language, end=" ")

"""
English French Spanish German Twi 
"""

tup = (1, 2, [1, 2, 3])
tup[2].append(4)
print(tup)

"""
(1, 2, [1, 2, 3, 4])
"""

dict1 = {"a": 1, "b": 2}
dict2 = {"c": 3, "d": 4}
merged_dict = {**dict1, **dict2}
print(merged_dict)

"""
{'a': 1, 'b': 2, 'c': 3, 'd': 4}
"""