从Python的CSV文件中仅获取一列

Question

我正在尝试使用三列n行的csv，并仅将第一列的元素制作为可迭代的列表。 我遇到的问题是它正在接收一个看起来像这样的列表（在代码中为“ datalist”）：

[
    ['56529.132', '16.9199', '0.152425'], ['56529.133', '16.4637', '0.127646'],
    ['56529.139', '16.4859', '0.12598'],  ['56529.139', '16.4011', '0.121806'],
    ['56529.147', '16.7835', '0.31821'],  ['56529.148', '16.3248', '0.179531'],
    ['56529.155', '16.3012', '0.146556'], ['56529.162', '16.1506', '0.174568'],
    ['56529.169', '16.1904', '0.180294'], ['56529.17', '16.0262', '0.164397'],
]

并将第一列隔离为如下所示：

56529.132
56529.133
56529.139
56529.139
56529.147
56529.148
56529.155
56529.162
56529.169
56529.17

在第二个输出中，每个单独的字符本身就是数据的一个元素，因此，如果我将其放入想要的列表中，则它看起来像：

['5']
['6']
['5']
['2']
['9']
['.']
['1']
['3']
['2']
['5']
['6']
['5']
['2']
['9']
['.']
['1']
['3']
['3']
['5']
['6']
['5']
['2']
['9']
['.']
['1']
['3']
['9']
['5']
['6']
['5']
['2']
['9']
['.']
['1']
['3']
['9']
['5']
['6']
['5']
['2']
['9']
['.']
['1']
['4']
['7']
['5']
['6']
['5']
['2']
['9']
['.']
['1']
['4']
['8']
['5']
['6']
['5']
['2']
['9']
['.']
['1']
['5']
['5']
['5']
['6']
['5']
['2']
['9']
['.']
['1']
['6']
['2']
['5']
['6']
['5']
['2']
['9']
['.']
['1']
['6']
['9']
['5']
['6']
['5']
['2']
['9']
['.']
['1']
['7']

我该如何解决？ 我需要一个“完整”的元素列表，所以看起来像

[['56529.132'],['56529.133'],['56529.139'],...

到目前为止，我的代码：

def read_csvfile(filename):
    import csv
    with open(filename) as csvfile:
        reader = csv.reader(csvfile, delimiter='\t')
        datalist = list(reader)
    return datalist

in_confirm = read_csvfile('bin3test.csv')

def confirm_obs(in_confirm):

    for row in in_confirm:
        col1 = row[0]
        print(col1)


result = confirm_obs(in_confirm)

CSV中的一些数据：

56529.132   16.9199 0.152425
56529.133   16.4637 0.127646
56529.139   16.4859 0.12598
56529.139   16.4011 0.121806
56529.147   16.7835 0.31821
56529.148   16.3248 0.179531
56529.155   16.3012 0.146556
56529.162   16.1506 0.174568
56529.169   16.1904 0.180294
56529.17    16.0262 0.164397

Answer 1

给定in_confirm（也是数据列表）：

first_values = [ [x[0].split()[0]] for x in in_confirm ]

如果您不需要可变的数据结构，则最好使用元组：

first_values = [ (x[0].split()[0],) for x in in_confirm ]

但是是的，最好解决读取时的定界符问题。

Answer 2

我会得到这样的第一行：

first_col = [row[0] for row in in_confirm]

然后，我将使用以下两种方法之一来获取单个字符/数字（不确定要使用哪种方法）：

[x for item in first_col for x in item]
# ['5', '6', '5', '2', '9', '.', '1', '3', '2', '5', ...

[[x] for item in first_col for x in item]
# [['5'], ['6'], ['5'], ['2'], ['9'], ['.'], ...