luliyu-python-day09

import os
# pip install requests
import requests
if not os.path.exists('data'):
    os.makedirs("data")
# f = open('./data/hello.txt', mode='w', encoding='UTF-8')
# f.write(text)
# f.close()
# 自动close
# 文本写入
text = input("输入")

with open('./data/hello.txt', mode='w', encoding='UTF-8') as f:
    f.write(text)

# 二进制写入
response = requests.get('https://t7.baidu.com/it/u=508006830,4042443322&fm=193&f=GIF')
data = response.content
print(data)

with open('./data/bumeinv.jpg', mode='wb') as f:
    f.write(data)


# 读取
with open('./data/hello.txt', mode='r', encoding='UTF-8') as f:
    du = f.read()
    print(du)

词频统计

## 词频统计案例
# 读取
with open('./data/hello.txt', mode='r', encoding='UTF-8') as f:
    text = f.read()
    print(text)
    text = text.replace(",", "")
    print(text)
    ts = text.split()
    print(ts)
    # {"When: 10, }
    counts = {}
    for word in ts:
        counts[word] = counts.get(word, 0) + 1
    print(counts)

匿名函数和高阶函数

# 匿名函数 :
# lambda 参数1, 参数2..... : 表达式
s = lambda x, y : x + y
print(s(100, 200))
# 高阶函数: 函数的参数中有函数作为参数
# def add(x, y):
#     return x + y
# def sub(x, y):
#     return x - y
# def mul(x, y):
#     return x * y
# def div(x, y):
#     return x / y
# print(add(10, 20))
# siZe就是高阶函数
def siZe(x, y, func):
    return func(x, y)
# print(siZe(100, 20, mul))
print(siZe(9, 5, func=lambda a, b: a*b))
print(siZe(9, 5, func=lambda a, b: a+b))

系统高阶函数

# 系统高阶函数
# map 函数接收两个参数, 第一个是一个function, 第二个是一个序列
# map是讲function 依次作用于序列中的每个元素
# ls = [i for i in range(10)]
# print(ls)
# def processing(x):
#     return x**2
# print(list(map(processing, ls)))
# print(list(map(lambda x:x**2, ls)))
print(list(map(lambda x: x**2, [i for i in range(10)])))
print(list(map(str, [i for i in range(10)])))
print(list(map(abs, [i for i in range(-10, 5)])))

# reduce
from functools import reduce
print(reduce(lambda x, y: x + y, [i for i in range(101)]))
print(reduce(lambda x, y: x * y, [i for i in range(10)]))
print(reduce(lambda x, y: x * y, [i for i in range(1, 6)]))

# filter
from random import randint
scores = [randint(10, 100) for _ in range(10)]
print(scores)
print(list(filter(lambda x: x>=60, scores)))
print(list(filter(lambda x: x%2==0, scores)))

排序函数

from random import randint, choice
import string
print(string.ascii_letters)
scores = [randint(10, 100) for _ in range(10)]
print(scores)
print(sorted(scores))
print(sorted(scores, reverse=True))
print(scores)
# sorted返回新的排序结果, 不会影响原来的

p_list = []
res = string.ascii_letters
for _ in range(5):
    info = {"name":choice(res), "score":randint(10, 100), "sal":randint(3000, 10000)}
    p_list.append(info)
for x in p_list:
    print(x)

res = sorted(p_list, key=lambda x:x['sal'], reverse=True)
print("#"*100)
for x in res:
    print(x)