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
#----------------------------------------------------------------------
import numpy
#----------------------------------------------------------------------
def StringToDoubleArray(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
"""
from StringIO import StringIO
import re
DataArray=numpy.empty([0],numpy.float64)
if len(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+-]$', " ", doublestring, count=0, flags=re.IGNORECASE)
#去掉首尾空格
doublestring=doublestring.strip()
if len(doublestring)>0:
StrIOds=StringIO(doublestring)
DataArray= numpy.genfromtxt(StrIOds)
return DataArray
#----------------------------------------------------------------------
def GetDoubleListFromString(String):
"""
#使用换行符分割字符串
#将字符串中的所有非Double类型的字符全部替换成空格
#以'#'开头注释直至行尾,都被清空
#将每一行转换成numpy.array数组
#返回numpy.array数组的列表
"""
from StringIO import StringIO
import re
DoubleList=[]
StringList=String.split('\n')#使用换行符分割字符串
for Line in StringList:
if len(Line.strip())>0:
#清空注释行,都是以'#'开头子字符
doublestring=re.sub('#.*$', " ", 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()
if len(doublestring)>0:
StrIOds=StringIO(doublestring)
DoubleList.append(numpy.genfromtxt(StrIOds))
return DoubleList
#----------------------------------------------------------------------
def GetDoubleListFromFile(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)
return DoubleList
def dlmread(FileName,dtype=numpy.float64):
"""
#Load Data From Txt-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
#Return Value: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
for dL in DoubleList:
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)
for i in row:
for j in colum:
DoubleArray[i][j]=DoubleList[i][j]
return DoubleArray
#----------------------------------------------------------------------
def loadtxtdata(filename,delimiter=""):
"""
#Load Data From Txt-File with delimiter.
#分隔符默认是:";",",",空格类 (包括\t)和自定义的delimiter等
#Return Value: 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
"""
from StringIO import StringIO
import re
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
for RChar in DelimiterALL:
LinesALL=LinesALL.replace(RChar,SpaceString)
return numpy.genfromtxt(StringIO(LinesALL))
#----------------------------------------------------------------------
def savetxtdata(filename, X, fmt='%.8e', delimiter=' ', newline='\n'):
"""
Save Data To Txt-File.
"""
numpy.savetxt(filename, X, fmt=fmt, delimiter=delimiter, newline=newline)
return True
#----------------------------------------------------------------------
def dlmwrite(filename, X, fmt='%.8e', delimiter=' ', newline='\n'):
"""
Save Data To Txt-File.
"""
numpy.savetxt(filename, X, fmt=fmt, delimiter=delimiter, newline=newline)
return True
#----------------------------------------------------------------------
#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.
