python使用正则搜索字符串或文件中的浮点数代码实例

用python和numpy处理数据次数比较多,写了几个小函数,可以方便地读写数据:

#-*-coding:utf-8-*-
#----------------------------------------------------------------------
#FileName:gettxtdata.py
#功能:读取字符串和文件中的数值数据(浮点数)
#主要提供类似matlab中的dlmread和dlmwrite函数
#同时提供loadtxtdata和savetxtdata函数
#Data:2013-1-10
#Author:吴徐平
#----------------------------------------------------------------------
importnumpy
#----------------------------------------------------------------------
defStringToDoubleArray(String):
"""
#将字符串中的所有非Double类型的字符全部替换成空格
#以"#"开头注释直至行尾,都被清空
#返回一维numpy.array数组

"""
fromStringIOimportStringIO
importre

DataArray=numpy.empty([0],numpy.float64)

iflen(String.strip())>0:
#清空注释行,都是以"#"开头子字符
doublestring=re.sub("#.*$","",String,count=0,flags=re.IGNORECASE)
#删除非数字字符
doublestring=re.sub("[^0-9.e+-]","",doublestring,count=0,flags=re.IGNORECASE)
#去掉不正确的数字格式(代码重复是有必要的)
doublestring=re.sub("[.e+-](?=\s)","",doublestring,count=0,flags=re.IGNORECASE)
doublestring=re.sub("[.e+-](?=\s)","",doublestring,count=0,flags=re.IGNORECASE)
doublestring=re.sub("[e+-]$","",doublestring,count=0,flags=re.IGNORECASE)
doublestring=re.sub("[e+-]$","",doublestring,count=0,flags=re.IGNORECASE)
#去掉首尾空格
doublestring=doublestring.strip()
iflen(doublestring)>0:
StrIOds=StringIO(doublestring)
DataArray=numpy.genfromtxt(StrIOds)

returnDataArray

#----------------------------------------------------------------------
defGetDoubleListFromString(String):
"""
#使用换行符分割字符串
#将字符串中的所有非Double类型的字符全部替换成空格
#以"#"开头注释直至行尾,都被清空
#将每一行转换成numpy.array数组
#返回numpy.array数组的列表

"""
fromStringIOimportStringIO
importre

DoubleList=[]
StringList=String.split("\n")#使用换行符分割字符串
forLineinStringList:
iflen(Line.strip())>0:
#清空注释行,都是以"#"开头子字符
doublestring=re.sub("#.*$","",Line,count=0,flags=re.IGNORECASE)
#删除非数字字符
doublestring=re.sub("[^0-9.e+-]","",doublestring,count=0,flags=re.IGNORECASE)
#去掉不正确的数字格式(代码重复是有必要的)
doublestring=re.sub("[.e+-](?=\s)","",doublestring,count=0,flags=re.IGNORECASE)
doublestring=re.sub("[.e+-](?=\s)","",doublestring,count=0,flags=re.IGNORECASE)
doublestring=re.sub("[e+-]$","",doublestring,count=0,flags=re.IGNORECASE)
doublestring=re.sub("[e+-]$","",doublestring,count=0,flags=re.IGNORECASE)
#去掉首尾空格
doublestring=doublestring.strip()
iflen(doublestring)>0:
StrIOds=StringIO(doublestring)
DoubleList.append(numpy.genfromtxt(StrIOds))
returnDoubleList

#----------------------------------------------------------------------
defGetDoubleListFromFile(FileName):
"""
#将文本文件中的所有Double类型的字符全部替换成numpy.array数组
#每一行都是numpy.array数组
##返回numpy.array数组的列表
#注意:返回列表的每个元素又都是一个numpy.array数组
#注意:返回列表的每个元素(或文件每行)可以包含不同多个数的数字

"""
file=open(FileName,"r")
read_file=file.read()
file.close()
DoubleList=GetDoubleListFromString(read_file)
returnDoubleList

defdlmread(FileName,dtype=numpy.float64):
"""
#LoadDataFromTxt-File.
#分隔符默认是:";",",",空格类(包括\t)等等
#以#开头的被认为是注释,不会被读取
#ReturnValue:二维数值数组(numpy.ndarray)
#对文本中数据的排列格式要求最低,且容许出现注释字符,智能化程度最高,但速度较慢
"""
DoubleList=GetDoubleListFromFile(FileName)
dlsize=[]#每一行数组的大小
fordLinDoubleList:
dlsize.append(dL.size)

MinColumnSize=min(dlsize)#数组的最大列数
MaxColumnSize=max(dlsize)#数组的最小列数
#数组创建和赋值
DoubleArray=numpy.empty([len(DoubleList),MinColumnSize],dtype=dtype)

row=range(0,len(DoubleList))
colum=range(0,MinColumnSize)

foriinrow:
forjincolum:
DoubleArray[i][j]=DoubleList[i][j]

returnDoubleArray
#----------------------------------------------------------------------

defloadtxtdata(filename,delimiter=""):
"""
#LoadDataFromTxt-Filewithdelimiter.
#分隔符默认是:";",",",空格类(包括\t)和自定义的delimiter等
#ReturnValue:二维数值数组(numpy.ndarray)
#对文本中数据的排列格式要求较高,且不容许出现注释字符,智能化程度较低,但速度较快
"""
fromStringIOimportStringIO
importre

file_handle=open(filename,"r")
LinesALL=file_handle.read()#读入字符串
file_handle.close()

DelimiterALL=delimiter+",;"#分隔符
SpaceString=""#空格
forRCharinDelimiterALL:
LinesALL=LinesALL.replace(RChar,SpaceString)

returnnumpy.genfromtxt(StringIO(LinesALL))

#----------------------------------------------------------------------
defsavetxtdata(filename,X,fmt="%.8e",delimiter="",newline="\n"):
"""
SaveDataToTxt-File.
"""
numpy.savetxt(filename,X,fmt=fmt,delimiter=delimiter,newline=newline)
returnTrue

#----------------------------------------------------------------------
defdlmwrite(filename,X,fmt="%.8e",delimiter="",newline="\n"):
"""
SaveDataToTxt-File.
"""
numpy.savetxt(filename,X,fmt=fmt,delimiter=delimiter,newline=newline)
returnTrue

#----------------------------------------------------------------------
#测试程序
#----------------------------------------------------------------------
if__name__=="__main__":
#生成随机数
data=numpy.random.randn(3,4)
filename="D:/x.txt"
#写入文件
dlmwrite(filename,data)
x=GetDoubleListFromFile(filename)
print(x)
print(dlmread(filename))
y=StringToDoubleArray("79l890joj")
print(y)
z=loadtxtdata(filename)
print(z)

我只在python2.7中试过,如果要在python3.x中使用,可自行测试.