lambda表达式
定义函数（普通方式）
def f1(): return 123 f2 = lambda : 123 def f3(a1,a2): return a1+a2 定义函数（lambda表达式）
f4 = lambda a1,a2: a1+a2
示例：
def f1(x):
if x % 2 ==1:
return x + 100
else:
return x
ret = map(lambda x: x + 100 if x % 2 ==1 else x, [1,2,3,4])
# print(ret)
for i in ret:
print(i)
运算结果：
101
2
103
4
内置函数
1，abs()
绝对值
参数可以是：负数、正数、浮点数或者长整形
i = abs(-123) #绝对值 print(i) i = abs(-1.2) print(i) i = abs(1.2) print(i) i = abs(-11216.5) print(i) i = abs(11216.5) print(i) 运算结果： 123 1.2 1.2 11216.5 11216.5
2，all ()
循环参数
如果每个元素都为真，那么all的返回值为真
假: 0，None,"",[],(),{}, ==> 总结出；0,None,空值 为假
示例：
all(['a', 'b', 'c', 'd']) #列表list，元素都不为空或0 True all(['a', 'b', '', 'd']) #列表list，存在一个为空的元素 False all([0, 1,2, 3]) #列表list，存在一个为0的元素 False all(('a', 'b', 'c', 'd')) #元组tuple，元素都不为空或0 True all(('a', 'b', '', 'd')) #元组tuple，存在一个为空的元素 False all((0,1,2,3,4)) #元组tuple，存在一个为0的元素 False all([]) # 空列表 True all(()) # 空元组 True
3，any()
只有有一个真，则为真
def any(iterable): for i in iterable: if i: return False return True
示例：
any(['a', 'b', 'c', 'd']) #列表list，元素都不为空或0 True any(['a', 'b', '', 'd']) #列表list，存在一个为空的元素 True any([0, '', False]) #列表list,元素全为0,'',false False any(('a', 'b', 'c', 'd')) #元组tuple，元素都不为空或0 True any(('a', 'b', '', 'd')) #元组tuple，存在一个为空的元素 True any((0, '', False)) #元组tuple，元素全为0,'',false False any([]) # 空列表 False any(()) # 空元组 False
4，divmod(a,b)函数
divmod(a,b)方法返回的是a//b（除法取整）以及a对b的余数
li = divmod(10,3) print(li) 运算结果： (3, 1)
5，eval()
可以执行一个字符串形式的表达式；简单的表达式，可以给算出来
ret = eval("122+45+53") print(ret) 运算结果： 220 ret = eval("a + 60",{"a":99}) print(ret) 运算结果： 159
6，exec()
可以执行py代码 ；不会返回值，直接输出结果
exec("print("hello, world")") 运算结果： hello, world
7，filter()
对于序列中的元素进行筛选，最终获取符合条件的序列（需要循环）
(函数，可迭代的对象) 过滤器
示例：
法一：
def f1(x):
if x >22:
return True
else:
return False
ret = filter(f1,[11,22,33,44])
for i in ret:
print(i)
法二：
def f1(x): return x > 22 ret = filter(lambda x: x > 22, [11,22,33,44]) for i in ret: print(i) 运算结果： 33 44
8，map()
(函数，可以迭代的对象，让元素统一操作)
示例：
def f(x): return x * x r = map(f, [1, 2, 3, 4, 5, 6]) list(r)
[1, 4, 9, 16, 25, 36]
****************
def f1(x):
if x % 2 ==1:
return x + 100
else:
return x
ret = map(lambda x: x + 100 if x % 2 ==1 else x, [1,2,3,4])
# print(ret)
for i in ret:
print(i)
9，globals()
获取全局变量 globals()对象的值能修改
def f1(): name = 123 print(globals(name))
10，locals()
获取局部变量 locals()对象的值不能修改
def f1(): name = 123 print(locals(name))
11,isinstance()
判断对象是否存在某个类创建的
a = 10 def b(): pass print (isinstance(a,(int,str))) print (isinstance(a,(float,str))) print (isinstance(b,(str,int))) class c: pass obj = c() print (isinstance(obj,(c,int))) 运算结果： True False False True
12，__repr__
ascii对象的类中找 __repr__,获取其返回值
class Foo: def __repr__(self): return "hello" obj = Foo() r = ascii(obj) print(r)
运算结果：
hello
13，iter()
迭代方法，依次取值
obj = iter([11,22,33,44]) print(obj) r1 = next(obj) #next，取下一个值，一个变量里的值可以一直往下取，直到没有就报错 print(r1) r2 = next(obj) print(r2)
r3 = next(obj)
print(r3)
运算结果：
11
22
33
14，max（）
取最大值
li = ([11,22,33,44,1]) r = max(li) print(r) 运算结果： 44
15，min()
取最小值
li = ([11,22,33,44,1]) r = min(li) print(r) 运算结果： 1
16，pow(x，y)
求次方
i = pow(2,10) print(i) 运算结果： 1024
17,sum（）
求和
r = sum([11,22,33,44]) print(r) 运算结果： 110
18，round 四舍五入
ret = round(4.8) print(ret)
19，zip()
zip函数接受任意多个（包括0个和1个）序列作为参数，返回一个tuple列表
a = [1,2,3] b = [4,5,6] r = zip(a,b) # zip,让a,b值1 1对应 for i in r: print(i) 运算结果： (1, 4) (2, 5) (3, 6)
20，import()
导入
import math #入导math模块 math.floor() #调用math模块中的floor()函数 python from使用方法例如： from math import floor #导入math模块中的floor函数方法 floor() #调用floor()函数方法
21，sort()
排序
li = [11,33,55,22,55,] print(li) li.sort() print(li) 运算结果： [11, 33, 55, 22, 55] [11, 22, 33, 55, 55]
22,flush()
刷新内部缓冲区
示例：
f = open("foo.txt", "wb") print ("Name of the file:hello word "), f.name f.flush() f.close() 运算结果： Name of the file:hello word
23，read()
读取文件内容 (给read加上一个参数，指定要读取的最大行数)
示例：
f = open("a_f.dat","rb") data = f.read(10000) f.close()
24，readline（）
readline判断文件读取结束的方法
示例：
filename = raw_input('Enter your file name') #输入要遍历读取的文件路径及文件名 file = open(filename,'r') done = 0 while not done: aLine = file.readline() if(aLine != ''): print aLine, else: done = 1 file.close() #关闭文件
25，hash
hash对key的优化，相当于给输出一种哈希值
li = "sdglgmdgongoaerngonaeorgnienrg" print(hash(li))
26，callable
callable表示一个对象是否可执行
def f1(): #看这个函数能不能执行，能发挥True return 123 f1() r = callable(f1) print(r)
进制
r = bin(11) #二进制 print(r) r = oct(8) #八进制 print(r) i = int(10) #十进制 print(i) r = hex(14) #十六进制 print(r) 运算结果： 0b1011 0o10 10 0xe
进制转换
示例：
int(10) i = int('0b11',base=2) #二进制转换十进制 print(i) i = int('0o11',base=8) #八进制转换十进制 print(i) i = int('0xe',base=16) #十六进制转换十进制 print(i) 运算结果： 3 9 14
字节，字符串
示例：
#bytes("xxxx",encoding="utf-8") i = bytes("你好，世界",encoding="utf-8") print(i) 运算结果： b'xe4xbdxa0xe5xa5xbdxefxbcx8cxe4xb8x96xe7x95x8c'
chr() 数字转换成字符 # 只适用在ascii中
示例：
c = chr(253) print(c) 运算结果：
y
ord() 字符转换成数字# 只适用在ascii中
示例：
c = ord('x') print(c) 运算结果： 120
随机数：
import random print (random.random()) print (random.randint(1,2)) print (random.randrange(1,10))
随机验证码：
import random temp = "" for i in range(6): #生成 0—4的随机数 num = random.randrange(0,4) # 如果随机数是1 或 3，那么就在验证码中生成一个 0—9的随机数字 #否则，验证码中生成一个随机字母 if num == 3 or num== 1: rad2 = random.randrange(0,10) temp = temp + str(rad2) else: rad1 = random.randrange(65,91) c1 = chr(rad1) temp = temp + c1 print(temp)
文件操作
一，打开文件
二，操作文件
三，关闭文件
open (文件名，模式，编码)
格式：
f =open("文件名"，"r") # r 只读模式 data = f.read() f.close() peint(data)
打开文件的模式：
普通方式（python内部自动转换）
1）只读模式，r
f = open("ha.log","r") f.write("kdjaskjskasdksjdaksj") f.close
2)只写模式，w 【不可读，文件不存在则创建；存在则清空文件内容再写入】
f = open("ha1.log","w") f.write("sdhjf43dk3rfk") f.close()
3)只写模式，x 【不可读；文件不存在则创建；文件存在则报错】
f = open("ha2.log","w") f.write("dahhadiu3528") f.close()
4)追加模式【不可读；不存在的则创建；存在则追加到末尾】
f = open("ha2.log","a") f.write("666jjjksk") f.close()
以字节的方式（二进制的方式）“b”
1)只读模式，rb 【文件不存在则创建；文件存在则清空内容】
f = open("ha.log","rb") data = f.read() f.close() print(data) str_data = str(data, encoding="utf-8") print(str_data)
2）只读模式，wb 【文件不存在则创建；存在则清空内容】
f = open("ha.log","wb") str_data = "中国人" bytes_data = bytes(str_data, encoding="utf-8") f.write(bytes_data) f.close()
同时读写文件 “+”
1）r+ 开始向后读，写时追加，指针调到最后
2）w+，先清空，再写，才可以读。写，指针到最后
3）x+如果文件存在则报错
4）a+，打开的同时指针已经移到最后，追加在最后
f.tell()#获取指针的位置
f.seek(num) #调整指针位置
f.write("")#写入
f.read("") # 读取
操作
1 class file(object) 2 def close(self): # real signature unknown; restored from __doc__ 3 关闭文件 4 """ 5 close() -> None or (perhaps) an integer. Close the file. 6 7 Sets data attribute .closed to True. A closed file cannot be used for 8 further I/O operations. close() may be called more than once without 9 error. Some kinds of file objects (for example, opened by popen()) 10 may return an exit status upon closing. 11 """ 12 13 def fileno(self): # real signature unknown; restored from __doc__ 14 文件描述符 15 """ 16 fileno() -> integer "file descriptor". 17 18 This is needed for lower-level file interfaces, such os.read(). 19 """ 20 return 0 21 22 def flush(self): # real signature unknown; restored from __doc__ 23 刷新文件内部缓冲区 24 """ flush() -> None. Flush the internal I/O buffer. """ 25 pass 26 27 28 def isatty(self): # real signature unknown; restored from __doc__ 29 判断文件是否是同意tty设备 30 """ isatty() -> true or false. True if the file is connected to a tty device. """ 31 return False 32 33 34 def next(self): # real signature unknown; restored from __doc__ 35 获取下一行数据，不存在，则报错 36 """ x.next() -> the next value, or raise StopIteration """ 37 pass 38 39 def read(self, size=None): # real signature unknown; restored from __doc__ 40 读取指定字节数据 41 """ 42 read([size]) -> read at most size bytes, returned as a string. 43 44 If the size argument is negative or omitted, read until EOF is reached. 45 Notice that when in non-blocking mode, less data than what was requested 46 may be returned, even if no size parameter was given. 47 """ 48 pass 49 50 def readinto(self): # real signature unknown; restored from __doc__ 51 读取到缓冲区，不要用，将被遗弃 52 """ readinto() -> Undocumented. Don't use this; it may go away. """ 53 pass 54 55 def readline(self, size=None): # real signature unknown; restored from __doc__ 56 仅读取一行数据 57 """ 58 readline([size]) -> next line from the file, as a string. 59 60 Retain newline. A non-negative size argument limits the maximum 61 number of bytes to return (an incomplete line may be returned then). 62 Return an empty string at EOF. 63 """ 64 pass 65 66 def readlines(self, size=None): # real signature unknown; restored from __doc__ 67 读取所有数据，并根据换行保存值列表 68 """ 69 readlines([size]) -> list of strings, each a line from the file. 70 71 Call readline() repeatedly and return a list of the lines so read. 72 The optional size argument, if given, is an approximate bound on the 73 total number of bytes in the lines returned. 74 """ 75 return [] 76 77 def seek(self, offset, whence=None): # real signature unknown; restored from __doc__ 78 指定文件中指针位置 79 """ 80 seek(offset[, whence]) -> None. Move to new file position. 81 82 Argument offset is a byte count. Optional argument whence defaults to 83 (offset from start of file, offset should be >= 0); other values are 1 84 (move relative to current position, positive or negative), and 2 (move 85 relative to end of file, usually negative, although many platforms allow 86 seeking beyond the end of a file). If the file is opened in text mode, 87 only offsets returned by tell() are legal. Use of other offsets causes 88 undefined behavior. 89 Note that not all file objects are seekable. 90 """ 91 pass 92 93 def tell(self): # real signature unknown; restored from __doc__ 94 获取当前指针位置 95 """ tell() -> current file position, an integer (may be a long integer). """ 96 pass 97 98 def truncate(self, size=None): # real signature unknown; restored from __doc__ 99 截断数据，仅保留指定之前数据 100 """ 101 truncate([size]) -> None. Truncate the file to at most size bytes. 102 103 Size defaults to the current file position, as returned by tell(). 104 """ 105 pass 106 107 def write(self, p_str): # real signature unknown; restored from __doc__ 108 写内容 109 """ 110 write(str) -> None. Write string str to file. 111 112 Note that due to buffering, flush() or close() may be needed before 113 the file on disk reflects the data written. 114 """ 115 pass 116 117 def writelines(self, sequence_of_strings): # real signature unknown; restored from __doc__ 118 将一个字符串列表写入文件 119 """ 120 writelines(sequence_of_strings) -> None. Write the strings to the file. 121 122 Note that newlines are not added. The sequence can be any iterable object 123 producing strings. This is equivalent to calling write() for each string. 124 """ 125 pass 126 127 def xreadlines(self): # real signature unknown; restored from __doc__ 128 可用于逐行读取文件，非全部 129 """ 130 xreadlines() -> returns self. 131 132 For backward compatibility. File objects now include the performance 133 optimizations previously implemented in the xreadlines module. 134 """ 135 pass 136 137 2.x
1 class TextIOWrapper(_TextIOBase): 2 """ 3 Character and line based layer over a BufferedIOBase object, buffer. 4 5 encoding gives the name of the encoding that the stream will be 6 decoded or encoded with. It defaults to locale.getpreferredencoding(False). 7 8 errors determines the strictness of encoding and decoding (see 9 help(codecs.Codec) or the documentation for codecs.register) and 10 defaults to "strict". 11 12 newline controls how line endings are handled. It can be None, '', 13 ' ', ' ', and ' '. It works as follows: 14 15 * On input, if newline is None, universal newlines mode is 16 enabled. Lines in the input can end in ' ', ' ', or ' ', and 17 these are translated into ' ' before being returned to the 18 caller. If it is '', universal newline mode is enabled, but line 19 endings are returned to the caller untranslated. If it has any of 20 the other legal values, input lines are only terminated by the given 21 string, and the line ending is returned to the caller untranslated. 22 23 * On output, if newline is None, any ' ' characters written are 24 translated to the system default line separator, os.linesep. If 25 newline is '' or ' ', no translation takes place. If newline is any 26 of the other legal values, any ' ' characters written are translated 27 to the given string. 28 29 If line_buffering is True, a call to flush is implied when a call to 30 write contains a newline character. 31 """ 32 def close(self, *args, **kwargs): # real signature unknown 33 关闭文件 34 pass 35 36 def fileno(self, *args, **kwargs): # real signature unknown 37 文件描述符 38 pass 39 40 def flush(self, *args, **kwargs): # real signature unknown 41 刷新文件内部缓冲区 42 pass 43 44 def isatty(self, *args, **kwargs): # real signature unknown 45 判断文件是否是同意tty设备 46 pass 47 48 def read(self, *args, **kwargs): # real signature unknown 49 读取指定字节数据 50 pass 51 52 def readable(self, *args, **kwargs): # real signature unknown 53 是否可读 54 pass 55 56 def readline(self, *args, **kwargs): # real signature unknown 57 仅读取一行数据 58 pass 59 60 def seek(self, *args, **kwargs): # real signature unknown 61 指定文件中指针位置 62 pass 63 64 def seekable(self, *args, **kwargs): # real signature unknown 65 指针是否可操作 66 pass 67 68 def tell(self, *args, **kwargs): # real signature unknown 69 获取指针位置 70 pass 71 72 def truncate(self, *args, **kwargs): # real signature unknown 73 截断数据，仅保留指定之前数据 74 pass 75 76 def writable(self, *args, **kwargs): # real signature unknown 77 是否可写 78 pass 79 80 def write(self, *args, **kwargs): # real signature unknown 81 写内容 82 pass 83 84 def __getstate__(self, *args, **kwargs): # real signature unknown 85 pass 86 87 def __init__(self, *args, **kwargs): # real signature unknown 88 pass 89 90 @staticmethod # known case of __new__ 91 def __new__(*args, **kwargs): # real signature unknown 92 """ Create and return a new object. See help(type) for accurate signature. """ 93 pass 94 95 def __next__(self, *args, **kwargs): # real signature unknown 96 """ Implement next(self). """ 97 pass 98 99 def __repr__(self, *args, **kwargs): # real signature unknown 100 """ Return repr(self). """ 101 pass 102 103 buffer = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 104 105 closed = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 106 107 encoding = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 108 109 errors = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 110 111 line_buffering = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 112 113 name = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 114 115 newlines = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 116 117 _CHUNK_SIZE = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 118 119 _finalizing = property(lambda self: object(), lambda self, v: None, lambda self: None) # default 120 121 3.x
关闭文件
with open ("ha.log","r") as f : f.read()
同时打开两个文件（2.7以上版本）
with open('log1','r') as obj1, open('log2', 'r') as obj2: pass with open('源文件','r') as obj1, open('新文件', 'w') as obj2: for line in obj1: obj2.write(line)
详细请参考：http://www.cnblogs.com/wupeiqi/articles/4943406.html
http://www.cnblogs.com/wupeiqi/articles/4911365.html