python读写csv文件方法详细总结

sudo pip install pandas

sudo pip3 install pandas

#encoding:utf-8import csv #读取csv文件csv_file = csv.reader(open('../../data/capital/2010-Q4-cabi-trip-history-data.csv'))print(csv_file) #添加newline可以避免一行之后的空格,这样需要在python3环境下运行out = open('../../data/capital/2010-Q4','a',newline='')csv_write = csv.writer(out,dialect='excel') for item in csv_file:	#print item	csv_write.writerow(item) print("write over")

#encoding:utf-8import csv #下面这种加了encoding的写法需要在python3环境下运行csv_reader = csv.reader(open('../../data/capital/2011-Q1-cabi-trip-history-data.csv',encoding='utf-8')) out = open('../../data/capital/a0','w',newline='')csv_writer = csv.writer(out,dialect='excel')  for row in csv_reader:	#输出的每一行是一个list,list中的每一个元素转换成了string类型	print(row)		csv_writer.writerow(row)

#encoding:utf-8import csv #读取csv文件方式1csvFile = open('../../data/capital/2011-Q3-cabi-trip-history-data.csv','r')reader = csv.reader(csvFile) data = [] for item in reader:#	print(item)	data.append(item) #print(data) csvFile.close()  #读取csv文件方式2with open("../../data/capital/2011-Q3-cabi-trip-history-data.csv",'r') as csvFile:	#读取csv文件,返回的是迭代类型	reader2 = csv.reader(csvFile)	for item2 in reader2:		print(item2)csvFile.close()  #从列表写入csv文件#设置newline,否则两行之间会空一行csvFile2 = open('../../data/capital/0001.csv','w',newline='')writer = csv.writer(csvFile2)m = len(data)for i in range(m):	writer.writerow(data[i])csvFile2.close()  #从字典写入csv文件dic = {'张三':123,'李四':456,'王二娃':789}csvFile3 = open('../../data/capital/0001.csv','w',newline='')writer2 = csv.writer(csvFile3)for key in dic:	print(key)#	writer2.writerow([key,dic[key]]) csvFile3.close()

#encoding:utf-8'''import pandas as pd#任意的多组列表a = [1,2,3]b = [4,5,6]#字典中的key值即为csv中的列名dataFrame = pd.DataFrame({'a_name':a,'b_name':b})#将DataFrame存储为csv,index表示是否显示行名,default=TruedataFrame.to_csv('0001.csv',index=False,sep='')#pandas提供的读取csv的方法data = pd.read_csv('test.csv')'''  #===================================#另一种方法:用csv包,一行一行写入import csv #python2可以用file替代openwith open('test.csv','w') as csvFile:	writer = csv.writer(csvFile)	#先写columns_name	writer.writerow(["index","a_name","b_name"])	#写入多行用writerows	writer.writerows([[1,2,3],[0,1,2],[4,5,6]]) #用reder读取csv文件with open('test.csv','r') as csvFile:	reader = csv.reader(csvFile)	for line in reader:		print line

#encoding:utf-8import csv  with open('test.csv') as csvFile:	#readcsv = csv.reader(csvFile,delimiter='')	readcsv = csv.reader(csvFile)	#	rows= [row for row in readcsv]	for row in readcsv:		rows= [row for row in reader]		#print(row)#打印一行		print(row[0])#打印一行中的某个cell		print(row[0],row[1])#打印一行中的某个cell print('=================') with open('test.csv') as csvFile:	readCSV = csv.reader(csvFile)	cols1 = []	cols2 = [] 	cols3 = []	for row in readCSV:		col1 = row[0]			col2 = row[1]		col3 = row[2]				cols1.append(col1)		cols2.append(col2)		cols3.append(col3) print cols1print cols2print cols3

#encoding:utf-8import csv #第一种方法:使用reader函数,接收一个可迭代的对象(比如csv文件),能返回一个生成器,就可以从其中解析出csv的内容.eg:下面的代码可以读取csv的全部内容,以行为单位with open('test.csv','rb') as csvFile:	reader = csv.reader(csvFile)	rows = [row for row in reader] print rows  print('===========') #提取其中某一列可以使用下面的方法with open('test.csv','rb') as csvFile:	reader = csv.reader(csvFile)	column = [row[1] for row in reader]print column   print('======第二种方法======')#第二种方法:使用DictReader,和reader函数类似,接收可迭代的对象,能返回一个可迭代的对象,能返回一个生成器,但是返回的每一个单元格都放在一个字典的值内,而这个字典的键则是这个单元格的标题.用下面的代码可以看到DictReader的结构:with open('test.csv','rb') as csvFile:	reader = csv.DictReader(csvFile)	column = [row for row in reader]print(column) #使用CictReader读取csv的某一列,这样可以按照列的标题查询with open('test.csv','rb') as csvFile:	reader = csv.DictReader(csvFile)	column = [row['a_name'] for row in reader]print column

#encoding:utf-8import csv with open('test.csv','rb') as csvFile:	reader = csv.reader(csvFile)	for row in reader:		print row #向csv文件中写内容,这样写会把内容全部写到一个cell中with open('test1.csv','wb') as csvFile:	writer = csv.writer(csvFile,delimiter=' ',quotechar='|',quoting=csv.QUOTE_MINIMAL)	writer.writerow(['a','4','5','6'])	writer.writerow(['b','1','2','3'])	writer.writerow(['c','9','8','7'])	writer.writerow(['d','8','3','1'])  #向csv文件中写内容,下面的写法最终可以把每一列的内容放在一个cell中with open('test2.csv','wb') as csvFile:	writer = csv.writer(csvFile,dialect='excel')	writer.writerow(['a','4','5','6'])	writer.writerow(['b','1','2','3'])	writer.writerow(['c','9','8','7'])	writer.writerow(['d','8','3','1'])