Python笔记

#coding:utf-8
a = raw_input()
try:
    if int(a) > 0:
      print '输入为正数'
    elif int(a) < 0:
        print '输入为负数'
    else:
        print '输入为0'
except Exception,e:
    print '请输入数字'

　　抓取异常，Python缩进格式要求严格，与Java不同，可以理解Python中的缩进格式与Java的{}相当

# coding:utf-8
i = 0
a = []
for i in range(3):
    print '请输入数字：'
    b = raw_input()
    a.append(b)
    if float(b) > 100:
        print b, '请输入1到100的整数', a

    elif float(b) < 0:
        print b, '请输入1到100的正整数', a

    else:
        print b, '符合要求'
        break
else:
    print '输入次数超出！'
# a = [1.0, 2.3, 3.3]
try:
    print '输入字符长度为：', len(a)
    i = 0
    b = 0
    while i in range(len(a)):
        print '第', i, '个字为', a[i]
        b += float(a[i])
        i += 1
        c = b / len(a)
    print '平均值为:', c
except Exception:
    print '请输入正确内容'

　　Python循环跳出使用break

　　新建文件并输入文件内容

#!/usr/bin/env python
# coding:utf-8
'makeTextFile.py -- create text file'

import os

ls = os.linesep
print ls
# get filename
while True:
    fname = raw_input('请输入文件名:')
    if os.path.exists(fname):
        print "ERROR: '%s' already exists" % fname
    else:
        break

# get file content (text) lines
all = []
print "
Enter lines (输入'.'结束).
"

# loop until user terminates input
i = 1
while i > 0:
    print '输入第', i, '行'
    entry = raw_input()
    i += 1
    if entry == '.':
        break
    else:
        all.append(entry)
    # write lines to file with proper line-ending
    fobj = open(fname, 'w')
    fobj.writelines(['%s%s' % (x, ls) for x in all])
    fobj.close()
    print 'DONE!'

 文件读取

#!/usr/bin/env Python
# coding:utf-8
'readFile.py--read and display'
# get filename

# attempt to open file for reading
while True:
    fname = raw_input('Enter filename:')
    print
    try:
        fobj = open(fname, 'r')
    except IOError, e:
        print '文件读取错误', e
    else:
        # display contents in fobj:
        for eachLine in fobj:
            print eachLine,
        fobj.close()
        break

 选择功能

#!/usr/bin/env python
# coding:utf-8
'makeTextFile.py -- create text file'

import os

ls = os.linesep
print ls
# get filename
# 选择功能
while True:
    type = int(raw_input('请输入功能类型：1为创建文件，2为读取文件，输入0退出程序：'))
    if type == 1:
        while True:
            fname = raw_input('请输入文件名:')
            if os.path.exists(fname):
                print "ERROR: '%s' already exists" % fname
            else:
                break

                # get file content (text) lines
        all = []
        print "
Enter lines (输入'.'结束).
"

        # loop until user terminates input
        i = 1
        while i > 0:
            print '输入第', i, '行'
            entry = raw_input()
            i += 1
            if entry == '.':
                break
            else:
                all.append(entry)
                # write lines to file with proper line-ending
            fobj = open(fname, 'w')
            fobj.writelines(['%s%s' % (x, ls) for x in all])
            fobj.close()
            print 'DONE!'
    elif type == 2:
        'readFile.py--read and display'
        # get filename

        # attempt to open file for reading
        while True:
            fname = raw_input('Enter filename:')
            print
            try:
                fobj = open(fname, 'r')
            except IOError, e:
                print '读取该文件名错误', e
            else:
                # display contents in fobj:
                for eachLine in fobj:
                    print eachLine.strip(),  # 去除每行末尾空白
                fobj.close()
                break
    elif type == 0:
        break
    else:
        print '请输入正确内容'

 *Python参数定义顺序必须是：必填参数，默认参数，可变参数，关键字参数

*args 是可变参数，args接收的是一个tuple元祖
**kw 是关键字参数，kw接收的是一个dict字典

Python使用map将首字母大写

# coding:utf-8
name = ['admIn', 'asdOJojnqg12', 'usEr']


def cF(s):
    b = ''
    if isinstance(s, str):
        for a in range(len(s)):
            if a == 0:
                b = b + s[0].upper()
            else:
                b = b + s[a].lower()
        return b
    else:
        return 'please input a string!'


l = map(cF, name)
print l

 Python内建的 filter() 函数用于过滤序列：删除序列中指定元素，通过传入的值为true或false判断

如：使用filter过滤1到100的质数

def isPrime(n):
  if n <= 1:
    return True
  i = 2
  while i*i <= n:
    if n % i == 0:
      return True
    i += 1
  return False


l = []
for i in range(100):
    l.append(i)
print filter(isPrime, l)

functools.partial 的作用就是，把一个函数的某些参数给固定住（也就是设置默认值），返回一个新的函数，调用这个新函数会更简单

#抓取文件

#!/usr/bin/env python
import os, shutil, time
cwd = os.getcwd()
path = '/opt/datasve'
src = '/opt/ePMS710_data'
if os.path.exists(path):
    pass
else:
    os.makedirs(path)
os.chdir(src)
while True:
    try:
        for a in os.listdir(src):
            # print a
            shutil.copy(a, path)
    except IOError:
        print 'ERROR'
        continue
    time.sleep(4)

 利用Python实现抓取TXT以及excel文档中的高频词组进行数据分析：

#  coding=utf-8
import jieba
import xlrd
import sys
reload(sys)
sys.setdefaultencoding('utf-8')
class wordCatch(object):
    def word_frequence(self, filename):

        if filename.endswith('.txt'):
            t = ''
            word = open(filename, 'r')
            for eachline in word:
                t += eachline
        elif filename.endswith('.xlsx') or filename.endswith('.xls'):
            word = xlrd.open_workbook(filename)
            table = word.sheets()[1]
            ncols = table.ncols
            nrows = table.nrows
            l = []
            for i in range(1, nrows):
                for j in range(1,ncols):
                    row = table.cell(i, j).value
                    # print row
                    l.append(row)
            t = ''.join(map(str, l))
        else:
            print '文件格式不支持，请联系作者！'

        nt = ''
        for s in t:
            if not s.isalpha():
                nt += s
        from collections import Counter
        words = [word for word in jieba.cut(nt, cut_all=True) if len(word) > 2  ]
        c = Counter(words)

        for word_freq in c.most_common(100):
            word, freq = word_freq
            print word, '出现', freq, '次'
a = wordCatch()
b='C:UsersAdministratorDesktopAb.xlsx'
a.word_frequence(b)

 Python if 语句：

　　Python程序语言指定任何非0和非空（null）值为true，0 或者 null为false

如果if条件为一个对象时，系统会自动将其转为对应的boolean类型

Python修改字典内对应键值类型：

#传入字典中的长整型修改为字符串
        for i in range(len(value.keys())):
            bigintvalue = ['updateTime', 'startTime', 'endTime', 'createTime', 'findTime', 'defectId']
            if value.keys()[i] in bigintvalue:
                value[value.keys()[i]] = str(value[value.keys()[i]])
                print value.items()[i]

 Python获取当前用户桌面路径

import os
print os.path.join(os.path.expanduser("~"), "Desktop")

 Python两个文件不能交叉引用