将一列的 CSV 文件转换为多列的 ASCII 文件

Question

test3.csv 包含一列，包含 33 个数字。我想将一列重塑为 11 行和 3 列。然后，我想将行和列保存为新的 ascii 文件，如附加图像。

第一次尝试：

import csv
f = open('test3.csv')
csv_f = csv.reader(f)
for row in csv_f:
    print row /* The result is 

结果是：

['0.000016'] ['0.000045'] ['0.000062'] ['0.000063'] ['0.000063'] ['0.000063']... **[' ']** means string?

第二次尝试：

f = open('test3.csv')
csv_f = csv.reader(f)
for row in csv_f:
    print row[0]

结果是：

0.000016 0.000045 0.000062 0.000063 0.000063 0.000063 ...I think they are number.

第三次尝试：

import csv
import numpy as np
f = open('test3.csv')
csv_f = csv.reader(f) 
a1 = [] 
for row in csv_f:
    a1.append(row[0])
print a1

结果是：

['0.000016', '0.000045', '0.000062', '0.000063', '0.000063', '0.000063',...].

其实我想把这个结果写成 ascii 文件，比如：

Answer 1

这里有一些代码可以满足你的需要：

代码：

import csv

# read each line of the input csv
with open('file3') as f:
    csv_f = csv.reader(f)

    # convert the first element of each line to a formated float
    numbers = ['%.6f' % float(row[0]) for row in csv_f]

# make sure the length is divisible by 3
numbers += [''] * (-len(numbers) % 3)

# reorder to by 3
numbers = [(numbers[i], numbers[i+1], numbers[i+2])
           for i in range(0, len(numbers), 3)]

# print each line
for line in numbers:
    print(' '.join(line))

测试数据：

0.000016
0.000045
0.000062
0.000063
0.000063
0.000063
0.000079
0.000078
0.000045
0.000062
0.000062
0.000062
0.000062
0.000062
0.000062
0.000077
0.000073
0.000062
0.000062
0.000045
0.000063

结果：

0.000016 0.000045 0.000062
0.000063 0.000063 0.000063
0.000079 0.000078 0.000045
0.000062 0.000062 0.000062
0.000062 0.000062 0.000062
0.000077 0.000073 0.000062
0.000062 0.000045 0.000063

Answer 2

我利用this great answer：

from itertools import izip_longest

def grouper(iterable, n, fillvalue=None):
    args = [iter(iterable)] * n
    return izip_longest(*args, fillvalue=fillvalue)

with open('data.txt', 'r') as f:
    for group in grouper(f, 3, ''):
        print ' '.join([x.strip() for x in group])