python254
A. python 中from i import randint i 是什麼意思
相當於是取1~254的隨機數，然後如果得到的數大於等於170的話，就往後挪1，就達到你要的隨機效果了。 a = random.randint(1, 254) if a >= 170: a += 1
B. python 出現路徑已存在的錯誤
這個應該是你的dstDir中已經存在了和你srcDir相同的文件，我也遇到過這個情況
C. Python不能安裝ez_setup.py，提示錯誤,怎麼辦
需要進入你的python安裝路徑，更改裡面的代碼，再次用cmd運行安裝命令即可。
D. Python中，我想得到1~255隨機整數，用rand.randint(1,255)，但不想讓裡面170這個數出現，怎麼寫呢
1、可以使用while函數，對隨機進行循環
(4)python254擴展閱讀：
除了randint，random模塊中比較常用的方法還有：
1、random.random()
生成一個0到1之間的隨機浮點數，包括0但不包括1，也就是[0.0, 1.0)。
2、random.uniform(a, b)
生成a、b之間的隨機浮點數。不過與randint不同的是，a、b無需是整數，也不用考慮大小。
random.uniform(2.2, 6)
random.uniform(6,2.2)
這兩種參數都是可行的。
3、random.choice(seq)
從序列中隨機選取一個元素。seq需要是一個序列，比如list、元組、字元串。
random.choice([1, 4, 7, 2, 5, 8]) #list
random.choice('hello') #字元串
random.choice((1, 2, 3)) #元組
都是可行的用法。
E. 如何查看python是否安裝成功
直接在命令終端中輸入：
1python
如果成功進入python互動式命令行，則安裝成功。
如果報如下錯：
1command python not found
則可能是環境變數未設置的問題。
F. 怎麼樣在python多線程實現檢測伺服器
需要ping一個網段所有機器的在線情況，shell腳步運行時間太長，用python寫個多線程ping吧，代碼如下：
#!/usr/bin/python
#coding=utf-8
'''
Created on 2015-8-4
@author: Administrator
'''
import threading,subprocess
from time import ctime,sleep,time
import Queue
queue=Queue.Queue()
class ThreadUrl(threading.Thread):
def __init__(self,queue):
threading.Thread.__init__(self)
self.queue=queue
def run(self):
while True:
host=self.queue.get()
ret=subprocess.call('ping -c 1 -w 1 '+host,shell=True,stdout=open('/dev/null','w'))
if ret:
print "%s is down" % host
else:
print "%s is up" % host
self.queue.task_done()
def main():
for i in range(100):
t=ThreadUrl(queue)
t.setDaemon(True)
t.start()
for host in b:
queue.put(host)
queue.join()
a=[]
with open('ip.txt') as f:
for line in f.readlines():
a.append(line.split()[0])
#print a
b=['192.168.3.'+str(x) for x in range(1,254)] #ping 192.168.3 網段
start=time()
main()
print "Elasped Time:%s" % (time()-start)
#t2=threading.Thread(target=move,args=('fff',))
#threads.append(t2)
'''
for i in a:
print ctime()
ping(i)
sleep(1)
if __name__ == '__main__':
for t in range(len(a)):
#t.setDaemon(True)
threads[t].start()
#t.join()
print "All over %s" % ctime()
'''
G. 3進制轉換編碼（python環境下） 和 36進制轉換編碼
table={10:'A',11:'B',12:'C',13:'D',14:'E',15:'F'}
foriinrange(10):
table[i]=str(i)
defd2n(decimal_number,n):
"""10進制轉其他進制"""
globaltable
max_suppoerted=max(table.keys())+1
assertn<=max_suppoerted,'最大支持%s進制'%max_suppoerted
result=[]
div,mod=divmod(decimal_number,n)
result.append(table[mod])
whilediv>=n:
div,mod=divmod(div,n)
result.append(table[mod])
result.append(table[div])
result.reverse()
print''.join(result)
defn2d(number,n):
"""其他進制轉10進制"""
globaltable
reverse_table=dict([(v,k)fork,vintable.items()])
array=list(str(number))
array.reverse()
result=0
fori,xinenumerate(array):
result+=reverse_table[x]*(n**i)
printresult
d2n(254,2)
d2n(254,3)
d2n(254,16)
d2n(254,10)
n2d(100102,3)
n2d('FE',16)結果：
11111110
100102
FE
254
254
254
兩個函數組合實現任意兩個進制之間的轉換
36進制剛好要用完26個字母把table補齊了
H. python函數返回值為」id「：「23」，如何獲取23
最近遇到os.system()執行系統命令的情況，上網搜集了一下資料，整理如下，以備不時之需，同時也希望能幫到某些人。
一、python中的 os.system(cmd)的返回值與linux命令返回值（具體參見本文附加內容）的關系
大家都習慣用os.systemv()函數執行linux命令，該函數的返回值十進制數（分別對應一個16位的二進制數）。該函數的返回值與 linux命令返回值兩者的轉換關系為：該函數的返回值（十進制）轉化成16二進制數，截取其高八位（如果低位數是0的情況下，有關操作系統的錯誤碼共 131個，所以低位都是零），然後轉乘十進制數即為 linux命令返回值0。
例如：
os.system()返回值為0 linux命令返回值也為0.
os.system()返回值為256，十六位二進制數示為：00000001，00000000，高八位轉乘十進制為 1 對應 linux命令返回值 1
os.system()返回值為512，十六位二進制數示為：00000010，00000000，高八位轉乘十進制為 2 對應 linux命令返回值 2
......其它同理
os.system()返回值為32512，十六位二進制數示為：01111111，00000000，高八位轉乘十進制為 127 對應 linux命令返回值 127
........
/**********************************************************************************************************************/
問題：/bin/xxx.py是一個返回碼為1的程序。當python 程序使用os.system(」./bin/xxx.py」) 這樣調用的時候， 成功運行後os.system 的返回值出現了問題，變成了256 ，也就是0×100。而不是正常應該返回的1。
解決：查閱了文檔發現os.system()的返回為：
On Unix, the return value is the exit status of the process encoded in the format specified for wait().
而os.wait()的返回為：
a 16-bit number, whose low byte is the signal number that killed the process, and whose high byte is the exit status (if the signal number
is zero);
os.system的返回值並不是執行程序的返回結果。而是一個16位的數，它的高位才是返回碼。也就是說os.system()返回256即 0×0100，返回碼應該是其高位0×01即1。所以要獲取程序運行退出的值（比如C的main函數中的return 0），需要處理一下。
ret = os.system('./a.out')
ret >>= 8
這樣才能獲取到正確的返回值。另外還要注意：python獲取到的值是無符號整數，所以返回負值的時候，列印出來是很大的正值。比如返回-1，python 會獲取到255，-2則254，以此類推。所以最好就判斷是否為0就可以了，實在要判斷自己寫的c程序返回值，建議返回0,1,2,3等值，出錯返回 -1。
另外，我遇到一次明明處理好了返回值，c程序調試信息提示也該返回值0了，結果python獲取到的是 -1，而且無論c程序返回多少，python都獲取-1。後來排查c程序的問題，發現原來是因為我這個python程序本身是由另一個C程序調用的，而調 用它的那個C程序中將SIGCLD信號忽略了（這表明python是根據子進程退出時產生的信號來獲取返回值的），我將那個C程序的SIGCLD綁定到函 數，即使那個函數什麼也不做，python也能獲取到正確的返回值了。
/**********************************************************************************************************************/
linux命令執行後無論成功與否都有一個返回值：
如果為 0，則表示命令執行成功，其它值則表示錯誤，具體的錯誤碼含義如下：
"OS error code 1: Operation not permitted"
"OS error code 2: No such file or directory"
"OS error code 3: No such process"
"OS error code 4: Interrupted system call"
"OS error code 5: Input/output error"
"OS error code 6: No such device or address"
"OS error code 7: Argument list too long"
"OS error code 8: Exec format error"
"OS error code 9: Bad file descriptor"
"OS error code 10: No child processes"
"OS error code 11: Resource temporarily unavailable"
"OS error code 12: Cannot allocate memory"
"OS error code 13: Permission denied"
"OS error code 14: Bad address"
"OS error code 15: Block device required"
"OS error code 16: Device or resource busy"
"OS error code 17: File exists"
"OS error code 18: Invalid cross-device link"
"OS error code 19: No such device"
"OS error code 20: Not a directory"
"OS error code 21: Is a directory"
"OS error code 22: Invalid argument"
"OS error code 23: Too many open files in system"
"OS error code 24: Too many open files"
"OS error code 25: Inappropriate ioctl for device"
"OS error code 26: Text file busy"
"OS error code 27: File too large"
"OS error code 28: No space left on device"
"OS error code 29: Illegal seek"
"OS error code 30: Read-only file system"
"OS error code 31: Too many links"
"OS error code 32: Broken pipe"
"OS error code 33: Numerical argument out of domain"
"OS error code 34: Numerical result out of range"
"OS error code 35: Resource deadlock avoided"
"OS error code 36: File name too long"
"OS error code 37: No locks available"
"OS error code 38: Function not implemented"
"OS error code 39: Directory not empty"
"OS error code 40: Too many levels of symbolic links"
"OS error code 42: No message of desired type"
"OS error code 43: Identifier removed"
"OS error code 44: Channel number out of range"
"OS error code 45: Level 2 not synchronized"
"OS error code 46: Level 3 halted"
"OS error code 47: Level 3 reset"
"OS error code 48: Link number out of range"
"OS error code 49: Protocol driver not attached"
"OS error code 50: No CSI structure available"
"OS error code 51: Level 2 halted"
"OS error code 52: Invalid exchange"
"OS error code 53: Invalid request descriptor"
"OS error code 54: Exchange full"
"OS error code 55: No anode"
"OS error code 56: Invalid request code"
"OS error code 57: Invalid slot"
"OS error code 59: Bad font file format"
"OS error code 60: Device not a stream"
"OS error code 61: No data available"
"OS error code 62: Timer expired"
"OS error code 63: Out of streams resources"
"OS error code 64: Machine is not on the network"
"OS error code 65: Package not installed"
"OS error code 66: Object is remote"
"OS error code 67: Link has been severed"
"OS error code 68: Advertise error"
"OS error code 69: Srmount error"
"OS error code 70: Communication error on send"
"OS error code 71: Protocol error"
"OS error code 72: Multihop attempted"
"OS error code 73: RFS specific error"
"OS error code 74: Bad message"
"OS error code 75: Value too large for defined data type"
"OS error code 76: Name not unique on network"
"OS error code 77: File descriptor in bad state"
"OS error code 78: Remote address changed"
"OS error code 79: Can not access a needed shared library"
"OS error code 80: Accessing a corrupted shared library"
"OS error code 81: .lib section in a.out corrupted"
"OS error code 82: Attempting to link in too many shared libraries"
"OS error code 83: Cannot exec a shared library directly"
"OS error code 84: Invalid or incomplete multibyte or wide character"
"OS error code 85: Interrupted system call should be restarted"
"OS error code 86: Streams pipe error"
"OS error code 87: Too many users"
"OS error code 88: Socket operation on non-socket"
"OS error code 89: Destination address required"
"OS error code 90: Message too long"
"OS error code 91: Protocol wrong type for socket"
"OS error code 92: Protocol not available"
"OS error code 93: Protocol not supported"
"OS error code 94: Socket type not supported"
"OS error code 95: Operation not supported"
"OS error code 96: Protocol family not supported"
"OS error code 97: Address family not supported by protocol"
"OS error code 98: Address already in use"
"OS error code 99: Cannot assign requested address"
"OS error code 100: Network is down"
"OS error code 101: Network is unreachable"
"OS error code 102: Network dropped connection on reset"
"OS error code 103: Software caused connection abort"
"OS error code 104: Connection reset by peer"
"OS error code 105: No buffer space available"
"OS error code 106: Transport endpoint is already connected"
"OS error code 107: Transport endpoint is not connected"
"OS error code 108: Cannot send after transport endpoint shutdown"
"OS error code 109: Too many references: cannot splice"
"OS error code 110: Connection timed out"
"OS error code 111: Connection refused"
"OS error code 112: Host is down"
"OS error code 113: No route to host"
"OS error code 114: Operation already in progress"
"OS error code 115: Operation now in progress"
"OS error code 116: Stale NFS file handle"
"OS error code 117: Structure needs cleaning"
"OS error code 118: Not a XENIX named type file"
"OS error code 119: No XENIX semaphores available"
"OS error code 120: Is a named type file"
"OS error code 121: Remote I/O error"
"OS error code 122: Disk quota exceeded"
"OS error code 123: No medium found"
"OS error code 124: Wrong medium type"
"OS error code 125: Operation canceled"
"OS error code 126: Required key not available"
"OS error code 127: Key has expired"
"OS error code 128: Key has been revoked"
"OS error code 129: Key was rejected by service"
"OS error code 130: Owner died"
"OS error code 131: State not recoverable"
I. python中如何用用正則表達式表達251 254這種+3循環的數據
用range 指定步長為3