2.系统模块上

time时间模块

struct_localTime = time.localtime()
print(struct_localTime.tm_year)
print(struct_localTime)

# 结构化时间
struct_time = time.gmtime()
print(struct_time)

# 将结构化时间转为时间戳
timeStamp = time.mktime(time.localtime())
print(timeStamp)

# 将结构化时间转为字符串时间
str_time = time.strftime('%Y-%m-%d %X',time.localtime())
print(str_time)

#将字符串时间转为结构化时间
new_struct_tiem = time.strptime('2016:12:12:17:30:12','%Y:%m:%d:%X')
print(new_struct_tiem)

# 将结构化时间转为固定的格式
print(time.asctime())
# 将字符串时间转为固定的格式
print(time.ctime())

datetime模块

import datetime

print(datetime.datetime.now())

# 打印：2018-08-15 10:31:03.353421

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随机模块random

import random
# 取0到1浮点型
random_n = random.random()
print(random_n)
# 0.3599807964622119

limit_random = random.randint(1, 6)
print(limit_random)
# 1到6随机数

# 从列表中去一个数，概率为1/3
r_random = random.choice([1, 2, 3])
print(r_random)

# 从列表中取一系列数   取三个数字
s_random = random.sample([1, 2, 3, 4, 5, 66], 3)
print(s_random)


# 取任意范围的浮点型
u_random = random.uniform(1, 6)
print(u_random)

# 打乱列表顺序
list1 = [1, 2, 3, 4, 5]
new = random.shuffle(list1)
print(list1)

demo: 取随机验证码

import random

def getRandomCode():
    result = ''
    for i in range(5):
        num = random.randint(0, 9)
        asc_char = random.randint(65, 122)
        char = chr(asc_char)
        s = str(random.choice([num, char]))
        result += s

    return result


result = getRandomCode()
print(result)

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解决路径引用问题

import os, sys

if __name__ == '__main__':

    # 文件的路径
    print(__file__)
    # 文件的绝对路径
    abs_path = os.path.abspath(__file__)

    # os.path.dirname 查找上一层目录
    self_path = os.path.dirname(abs_path)
    print(self_path)

    BATH_DIR = os.path.dirname(self_path)
    print(BATH_DIR)
    # 临时添加目录
    sys.path.append(BATH_DIR)
    

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os模块

# 当前工作路径
 print(os.getcwd())
# 改变当前路径
 print(os.chdir('..'))
 print(os.getcwd())
...

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sys模块

argv获取用户输入参数

import os, sys

if __name__ == '__main__':

    print(sys.argv)
    path = sys.argv[0]
    command = sys.argv[1]

进度条:

import time, sys

if __name__ == '__main__':

    for i in range(100):
        # 向屏幕输出 会缓存
        sys.stdout.write('#')
        time.sleep(0.1)
        # 立即输出缓存内容
        s

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json模块

符合json规则的字符串：必须使用双引号["key":"value"]

import json

if __name__ == '__main__':

    dict1 = {'name': 'bill'}
    # 使用单引号会自动转为双引号
    jsonStr = json.dumps(dict1)
    print(jsonStr , type(jsonStr))

    raw = json.loads(jsonStr)
    print(raw , type(raw))

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pickle模块

同json相似，不过dump结果是bytes字节
序列化结果，不可读
pickle可序列化的种类比json更多

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shelve模块

import shelve

if __name__ == '__main__':

    # 生成固定三个文件，并存入已经序列化的数据
    f = shelve.open(r"new_file")
    f["name"] = "alex"
    f["age"] = 18
    f.close()

   ######### 分割线 #########

    file1 = shelve.open(r"new_file")
    # 取值
    name = file1.get("name")

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XML模块

标签语言

# 简写
import xml.etree.cElementTree as ET

tree = ET.parse("xml_lesson")
root = tree.getroot()
# 获取标签名字
root_tag = root.tag
# 获取标签属性
root_attr = root.attrib

for i in root:

    subNode = i


# 遍历修改某一标签
for node in root.iter("year"):
    new_year = int(node.text) + 1
    node.text = str(new_year)
    # 新增一个标签
    node.set("updated", "yes")
    
    
# 写入文件内容
tree.write("xml_lesson")


# 删除标签
for counrtyNode in root.findall("country"):
    rank = int(counrtyNode.find("rand").text)
    if rank > 50:
        root.remove(counrtyNode)
        
        
# 写入文件内容
tree.write("xml_lesson")

创建xml文件:

# 简写
import xml.etree.cElementTree as ET

# 创建xml

# 创建跟标签
new_xml = ET.Element("root")
name = ET.SubElement(new_xml,"name",attrib={"ecrolled":"yes"})
name.text = "bill"

# 生成文档对象
et = ET.ElementTree(new_xml)
et.write("test.xml",encoding="utf-8",xml_declaration=True)
# 打印生成的格式
ET.dump(new_xml)

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