如何获取我的列表以打印出每一行？

Question

I'm a little confused as to why this is not working. I'm trying to get my program to read every line out a csv file change it from a string to a float and then print it out line by line.

csv_list = open('example_data.csv','rb')
lists= csv_list.readlines()
csv_list.close()


for lines in lists:
    lists_1 = lists.strip().split()
    list_2 = [float(x) for x in lists_1]
print list_2

Any help would be appreciated.

Answer 1

First, don't use readlines . Simply iterate over file

for lines in csv_list:
   ...

second, use csv library for reading http://docs.python.org/2/library/csv.html

In your exapmple, it is csv, so don't split by whitespace but comma or semicolon.

Answer 2

Try this:

import pprint

with open('example_data.csv','rb') as csv_list:
    lists= csv_list.readlines()
    lists_1 = []
    lists_2 = []
    for lines in lists:
        lists_1.append(lines.strip().split())
        list_2.append([float(x) for x in lists_1])
    pprint.pprint(list_2)

Answer 3

for lines in lists:
    lists_1 = lines.strip().split()   # 'lines' here
    list_2 = [float(x) for x in lists_1]
    print list_2 # print your list in a loop

Answer 4

print list_2需要与循环的其余部分缩进同一级别，并且应该为lines.strip().split()

Answer 5

print list_2 is outside of the for loop. You need to indent it.

Answer 6

Judging by the file name, I assume that the fields in your file is separated by comma. If that is the case, you need to split the line using the comma:

    lists_1 = lists.strip().split(',')

Better yet, use the csv module. Here is an example:

import csv 

with open('example_data.csv', 'rb') as f:
    csvreader = csv.reader(f)
    for line in csvreader:
        line = [float(x) for x in line] # line is now a list of floats
        print line