1、内置函数
1.1Python的内置函数
1.2一阶段需要掌握的函数
2、随机验证码函数：
import random
#assii:大写字母：65~90，小写 97~122 数字48-57
tmp = ""
for i in range(6):
num =random.randrange(1,4)
if num == 1:
rad2 = random.randrange(0,10)
tmp = tmp+str(rad2)
elif num == 2:
rad3 = random.randrange(97, 123)
tmp = tmp + chr(rad3)
else:
rad1 = random.randrange(65,91)
c = chr(rad1)
tmp = tmp + c
print(tmp)
3、文件操作
使用open函数操作，该函数用于文件处理。
操作文件时，一般需要经历如下步骤：
打开文件
操作文件
关闭文件
3.1打开文件
open(文件名，模式，编码)eg：f = open("ha.log","a+",encoding="utf-8")注：默认打开模式r
3.2打开模式：
基本模式：
? r:只读模式（不可写）
? w：只写模式（不可读，不存在则创建，存在则清空内容（只要打开就清空））
? x：只写模式（不可读，不存在则创建，存在则报错）
? a：追加模式（不可读，不存在就创建，存在只追加内容）
二进制模式：rb\wb\xb\ab
特点：二进制打开，对文件的操作都需以二进制的方式进行操作
对文件进行读写
-
- r+， 读写【可读，可写】
- w+，写读【可读，可写】
- x+ ，写读【可读，可写】
- a+， 写读【可读，可写】
3.3 文件操作的方法
class TextIOWrapper(_TextIOBase):
"""
Character and line based layer over a BufferedIOBase object, buffer.
encoding gives the name of the encoding that the stream will be
decoded or encoded with. It defaults to locale.getpreferredencoding(False).
errors determines the strictness of encoding and decoding (see
help(codecs.Codec) or the documentation for codecs.register) and
defaults to "strict".
newline controls how line endings are handled. It can be None, ‘‘,
‘\n‘, ‘\r‘, and ‘\r\n‘. It works as follows:
* On input, if newline is None, universal newlines mode is
enabled. Lines in the input can end in ‘\n‘, ‘\r‘, or ‘\r\n‘, and
these are translated into ‘\n‘ before being returned to the
caller. If it is ‘‘, universal newline mode is enabled, but line
endings are returned to the caller untranslated. If it has any of
the other legal values, input lines are only terminated by the given
string, and the line ending is returned to the caller untranslated.
* On output, if newline is None, any ‘\n‘ characters written are
translated to the system default line separator, os.linesep. If
newline is ‘‘ or ‘\n‘, no translation takes place. If newline is any
of the other legal values, any ‘\n‘ characters written are translated
to the given string.
If line_buffering is True, a call to flush is implied when a call to
write contains a newline character.
"""
def close(self, *args, **kwargs): # real signature unknown
关闭文件
pass
def fileno(self, *args, **kwargs): # real signature unknown
文件描述符
pass
def flush(self, *args, **kwargs): # real signature unknown
刷新文件内部缓冲区
pass
def isatty(self, *args, **kwargs): # real signature unknown
判断文件是否是同意tty设备
pass
def read(self, *args, **kwargs): # real signature unknown
读取指定字节数据
pass
def readable(self, *args, **kwargs): # real signature unknown
是否可读
pass
def readline(self, *args, **kwargs): # real signature unknown
仅读取一行数据
pass
def seek(self, *args, **kwargs): # real signature unknown
指定文件中指针位置
pass
def seekable(self, *args, **kwargs): # real signature unknown
指针是否可操作
pass
def tell(self, *args, **kwargs): # real signature unknown
获取指针位置
pass
def truncate(self, *args, **kwargs): # real signature unknown
截断数据，仅保留指定之前数据
pass
def writable(self, *args, **kwargs): # real signature unknown
是否可写
pass
def write(self, *args, **kwargs): # real signature unknown
写内容
pass
def __getstate__(self, *args, **kwargs): # real signature unknown
pass
def __init__(self, *args, **kwargs): # real signature unknown
pass
@staticmethod # known case of __new__
def __new__(*args, **kwargs): # real signature unknown
""" Create and return a new object. See help(type) for accurate signature. """
pass
def __next__(self, *args, **kwargs): # real signature unknown
""" Implement next(self). """
pass
def __repr__(self, *args, **kwargs): # real signature unknown
""" Return repr(self). """
pass
buffer = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
closed = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
encoding = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
errors = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
line_buffering = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
name = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
newlines = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
_CHUNK_SIZE = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
_finalizing = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
3.x
3.4 管理上下文
使用open方法打开后要关闭文本。
with方法后，python会自动回收资源
py2.7以后的版本with方法支持同时对两个文件进行操作
eg：with open(‘log1‘) as obj1, open(‘log2‘) as obj2:
3.5 文件日常操作
open(文件名，模式，编码)
close()
flush():将内存中的文件数据写入磁盘
read():读取指针的内容
readline():只都一行内容
seek()定位指针位置
tell()获取当前指针位置
truncate() 截断数据，仅保留指定之前的数据，依赖于指针
write() 写入数据
3.6 文件操作示例代码
#!/usr/bin/env python
# -*- coding:utf-8 -*-
####基本操作方法
#默认是只读模式，默认编码方式：utf-8
# f = open(‘ha.log‘)
# data = f.read()
# f.close()
# print(data)
#只读，r
# f = open("ha.log","r")
# f.write("asdfs")
# f.close()
#只写，w ---存在就清空，打开就清空
# f = open("ha1.log","w")
# f.write("Hello world!")
# f.close()
#只写 ，x
# f = open("ha2.log","x")
# f.write("Hello world1!")
# f.close()
#追加 a,不可读
# f = open("ha2.log","a")
# f.write("\nHello world! a mode")
# f.close()
### 字节的方式打开
## 默认读取到的都是字节,不用设置编码方式
## 1、 只读，rb
# f = open("ha.log","rb")
# data =f.read()
# f.close()
# print(type(data))
# print(data)
# print(str(data,encoding="utf-8"))
#2 只写，wb
# f = open("ha.log","wb")
# f.write(bytes("中国",encoding="utf-8"))
# f.close()
### r+ ,w+,x+，a+
#r+
# f = open("ha.log",‘r+‘,encoding="utf-8")
# print(f.tell())
# data = f.read()
# print(type(data),data)
# f.write("德国人")
# print(f.tell())
# data = f.read()
# f.close()
#w+ 先清空，之后写入的可读，写后指针到最后
# f = open("ha.log","w+",encoding="utf-8")
# f.write("何莉莉")
# f.seek(0) # 指针调到最后
# data = f.read()
# f.close()
# print(data)
# x+ 功能类似w+，区别：若文件存在即报错
#a + 打开的同时指针到最后
f = open("ha.log","a+",encoding="utf-8")
print(f.tell())
f.write("SB")
print(f.tell())
data = f.read()
print(data)
f.seek(0)
data = f.read()
print(data)
print(type(data))
print(type(f))
f.close()
文件操作示例
4、lambda表达式
f1 = lambda x,y: 9+x
时间： 2024-10-25 11:56:48