python基本语法及使用

常用API

大小写

.lower() — 全部小写
.upper() — 全部大写
.title() — 各个字符的首字母大写
.capitalize() — 首字母大写

name = input()
print(name.lower())
print(name.upper())
print(name.title())

去除空格

.strip() — 删除两边空格
.lstrip() — 删除左边空格
.rstrip() — 删除右边空格
.replace(“ “,””) — 删除所有空格
.split() — 先切分，””.join() — 再拼接

print(input().strip())

不用循环语句的重复输出

使用*可以重复输出这段字符串

print(input() * 100)

截取字符串前 10 个字符

print(input()[0:10])

list 列表的添加和移除

offer_list = ['Allen', 'Tom']
for i in offer_list:
    print('{}, you have passed our interview and will soon become a member of our company.'.format(i))

offer_list.remove('Tom')
offer_list.append('Andy')

for i in offer_list:
    print('{}, welcome to join us!'.format(i))

slice 切片函数

group_list = [ 'Tom', 'Allen', 'Jane', 'William', 'Tony' ]

print(group_list[slice(0, 2)])
print(group_list[slice(1, 4)])
print(group_list[slice(3, 5)])

与或非

x, y = input().split()

print(x and y)
print(x or y)
print(not int(x))
print(not int(y))

成员与列表 in

line = input().split()
name = input()

print(name in line)

保存数据到文件

两种保存的方式

# fp = open('douban.json', 'w', encoding='utf-8')
# fp.write(content)

with open('douban1.json', 'w', encoding='utf-8') as fp:
    fp.write(content)

https://www.zhihu.com/question/56927648

for循环

for i in range(1, 6):
    print(i)

输出1-5，不包含6

function函数

定义函数使用def关键字

def my_abs(x):
    if x >= 0:
        return x
    else:
        return -x

print(my_abs(-99))

定义空函数

def nop():
    pass

定义main函数

if __name__ == "__main__":
    main()

requests的基本使用

response = requests.get(url=url, params=params, cookies=cookies, headers=headers)
# 需要转对应的编码，比如utf-8
content = response.content.decode('utf-8')

json的转换

content转换完毕之后可能需要再转成json对象，使用 json.loads 函数进行转换成dict对象

# {"status": "1", "state": "success", "data": [{"value": 7642}, {"value": 5199}, {"value": 4247}, {"value": 4604}, {"value": 3344}, {"value": 9769}, {"value": 6655}, {"value": 1263}, {"value": 3209}, {"value": 5533}]}
# content = response.content.decode('utf-8')
content = '{"status": "1", "state": "success", "data": [{"value": 7642}, {"value": 5199}, {"value": 4247}, {"value": 4604}, {"value": 3344}, {"value": 9769}, {"value": 6655}, {"value": 1263}, {"value": 3209}, {"value": 5533}]}'
print(content)
obj = json.loads(content)
    data_list = obj['data']
    for d in data_list:
        value = d['value']
        print(value)