python学习笔记2

创建一个文件并往里面写入内容

import os
# coding='utf-8'
#取得OS的换行符
ls = os.linesep
 
# 获取文件名
while True:
    fname = raw_input('input file name: ')
    if os.path.exists(fname):
        print "ERROR : '%s' already exists!" % fname
    else:
        break
print fname
#获取文件的内容
all = []
print "\nEnter lines('.' by iteslf to quit).\n"
 
#读取用户的输入
while True:
    entry = raw_input('> ')
    if entry == '.':
        break
    else:
        all.append(entry)
 
#写入文件
fobj = open(fname,'w')
fobj.writelines(['%s%s' % (x, ls ) for x in all])
fobj.close()
print "DONE"

读取文件内容并显示出来

# coding='utf-8'
# 获取文件名
fname = raw_input('input file name: ')
print fname
 
try:
    fobj = open(fname,'r')
except IOError, e:
    print "**** file open: ",e
else:
    for eachLine in fobj:
        print eachLine,
    fobj.close();

获取数值的类型.注意python作为高级语言,却没有对数值进行统一,还是分属于几个类型:整型,浮点型,长整型,复数

# coding='utf-8'
# 获取数值的类型
def getNumType(num):
    print num, 'is',
    #判定参数一是否为参数二当中的某个元素的实例
    if isinstance(num, (int,long,float,complex)):
        print 'a number of type: ',type(num).__name__
    else:
        print 'not a number at all'
         
getNumType(-68)
getNumType(99999999999999999999999999999L)
getNumType(98.6)
getNumType(-5.2+1.9j)
getNumType("1212")