在Python中从CSV文件中读取行

Question

我有一个CSV文件,下面是一个示例:

Year:  Dec: Jan:
1      50   60
2      25   50
3      30   30
4      40   20
5      10   10

我知道如何读取文件并打印每一列(例如 - ['Year', '1', '2', '3', etc]).但我真正想做的是读取行,这将是这样的['Year', 'Dec', 'Jan'],然后['1', '50', '60']依此类推.

然后我想将这些数字存储['1', '50', '60']到变量中,以便我可以在以后将它们合计为:

Year_1 = ['50', '60'].然后我就能做到sum(Year_1) = 110.

我将如何在Python 3中执行此操作？

Answer 1

使用csv模块:

import csv

with open("test.csv", "r") as f:
    reader = csv.reader(f, delimiter="\t")
    for i, line in enumerate(reader):
        print 'line[{}] = {}'.format(i, line)

输出:

line[0] = ['Year:', 'Dec:', 'Jan:']
line[1] = ['1', '50', '60']
line[2] = ['2', '25', '50']
line[3] = ['3', '30', '30']
line[4] = ['4', '40', '20']
line[5] = ['5', '10', '10']

Answer 2

这样的事情:

with open("data1.txt") as f:
    lis = [line.split() for line in f]        # create a list of lists
    for i, x in enumerate(lis):              #print the list items 
        print "line{0} = {1}".format(i, x)

# output 
line0 = ['Year:', 'Dec:', 'Jan:']
line1 = ['1', '50', '60']
line2 = ['2', '25', '50']
line3 = ['3', '30', '30']
line4 = ['4', '40', '20']
line5 = ['5', '10', '10']

要么 :

with open("data1.txt") as f:
    for i, line in enumerate(f):             
        print "line {0} = {1}".format(i, line.split())

# output         
line 0 = ['Year:', 'Dec:', 'Jan:']
line 1 = ['1', '50', '60']
line 2 = ['2', '25', '50']
line 3 = ['3', '30', '30']
line 4 = ['4', '40', '20']
line 5 = ['5', '10', '10']

编辑:

with open('data1.txt') as f:
    print "{0}".format(f.readline().split())
    for x in f:
        x = x.split()
        print "{0} = {1}".format(x[0],sum(map(int, x[1:])))

# output          
['Year:', 'Dec:', 'Jan:']
1 = 110
2 = 75
3 = 60
4 = 60
5 = 20

Answer 3

按列读取是否更难？

无论如何,这会读取该行并将值存储在列表中:

for line in open("csvfile.csv"):
    csv_row = line.split() #returns a list ["1","50","60"]

现代解决方案

# pip install pandas
import pandas as pd 
df = pd.read_table("csvfile.csv", sep=" ")

Answer 4

最简单的方法是这样：

from csv import reader

# open file in read mode
with open('file.csv', 'r') as read_obj:
    # pass the file object to reader() to get the reader object
    csv_reader = reader(read_obj)
    # Iterate over each row in the csv using reader object
    for row in csv_reader:
        # row variable is a list that represents a row in csv
        print(row)

output:
['Year:', 'Dec:', 'Jan:']
['1', '50', '60']
['2', '25', '50']
['3', '30', '30']
['4', '40', '20']
['5', '10', '10']

Answer 5

import csv

with open('filepath/filename.csv', "rt", encoding='ascii') as infile:
    read = csv.reader(infile)
    for row in read :
        print (row)

这将解决您的问题.别忘了给出编码.