现在有如下数据集存储在txt文件中，利用python逐行读取数据到list类型下。
1.658985 4.285136
-3.453687 3.424321
4.838138 -1.151539
-5.379713 -3.362104
0.972564 2.924086
-3.567919 1.531611
0.450614 -3.302219
-3.487105 -1.724432
2.668759 1.594842
-3.156485 3.191137
3.165506 -3.999838
-2.786837 -3.099354
4.208187 2.984927
-2.123337 2.943366
0.704199 -0.479481
-0.392370 -3.963704
2.831667 1.574018
-0.790153 3.343144
2.943496 -3.357075
-3.195883 -2.283926
2.336445 2.875106
-1.786345 2.554248
2.190101 -1.906020
-3.403367 -2.778288
1.778124 3.880832
-1.688346 2.230267
2.592976 -2.054368
-4.007257 -3.207066
2.257734 3.387564
-2.679011 0.785119
0.939512 -4.023563
-3.674424 -2.261084
2.046259 2.735279
-3.189470 1.780269
4.372646 -0.822248
-2.579316 -3.497576
1.889034 5.190400
-0.798747 2.185588
2.836520 -2.658556
-3.837877 -3.253815
2.096701 3.886007
-2.709034 2.923887
3.367037 -3.184789
-2.121479 -4.232586
2.329546 3.179764
-3.284816 3.273099
3.091414 -3.815232
-3.762093 -2.432191
3.542056 2.778832
-1.736822 4.241041
2.127073 -2.983680
-4.323818 -3.938116
3.792121 5.135768
-4.786473 3.358547
2.624081 -3.260715
-4.009299 -2.978115
2.493525 1.963710
-2.513661 2.642162
1.864375 -3.176309
-3.171184 -3.572452
2.894220 2.489128
-2.562539 2.884438
3.491078 -3.947487
-2.565729 -2.012114
3.332948 3.983102
-1.616805 3.573188
2.280615 -2.559444
-2.651229 -3.103198
2.321395 3.154987
-1.685703 2.939697
3.031012 -3.620252
-4.599622 -2.185829
4.196223 1.126677
-2.133863 3.093686
4.668892 -2.562705
-2.793241 -2.149706
2.884105 3.043438
-2.967647 2.848696
4.479332 -1.764772
-4.905566 -2.911070
代码如下：
file_name = "k-means.txt"
dataset = []
file = open(file_name, mode='r')
for line in file:
line = line.split()
dataset.append(line)
file.close()
print(dataset)
[['1.658985', '4.285136'], ['-3.453687', '3.424321'], ['4.838138', '-1.151539'], ['-5.379713', '-3.362104'], ['0.972564', '2.924086'], ['-3.567919', '1.531611'], ['0.450614', '-3.302219'], ['-3.487105', '-1.724432'], ['2.668759', '1.594842'], ['-3.156485', '3.191137'], ['3.165506', '-3.999838'], ['-2.786837', '-3.099354'], ['4.208187', '2.984927'], ['-2.123337', '2.943366'], ['0.704199', '-0.479481'], ['-0.392370', '-3.963704'], ['2.831667', '1.574018'], ['-0.790153', '3.343144'], ['2.943496', '-3.357075'], ['-3.195883', '-2.283926'], ['2.336445', '2.875106'], ['-1.786345', '2.554248'], ['2.190101', '-1.906020'], ['-3.403367', '-2.778288'], ['1.778124', '3.880832'], ['-1.688346', '2.230267'], ['2.592976', '-2.054368'], ['-4.007257', '-3.207066'], ['2.257734', '3.387564'], ['-2.679011', '0.785119'], ['0.939512', '-4.023563'], ['-3.674424', '-2.261084'], ['2.046259', '2.735279'], ['-3.189470', '1.780269'], ['4.372646', '-0.822248'], ['-2.579316', '-3.497576'], ['1.889034', '5.190400'], ['-0.798747', '2.185588'], ['2.836520', '-2.658556'], ['-3.837877', '-3.253815'], ['2.096701', '3.886007'], ['-2.709034', '2.923887'], ['3.367037', '-3.184789'], ['-2.121479', '-4.232586'], ['2.329546', '3.179764'], ['-3.284816', '3.273099'], ['3.091414', '-3.815232'], ['-3.762093', '-2.432191'], ['3.542056', '2.778832'], ['-1.736822', '4.241041'], ['2.127073', '-2.983680'], ['-4.323818', '-3.938116'], ['3.792121', '5.135768'], ['-4.786473', '3.358547'], ['2.624081', '-3.260715'], ['-4.009299', '-2.978115'], ['2.493525', '1.963710'], ['-2.513661', '2.642162'], ['1.864375', '-3.176309'], ['-3.171184', '-3.572452'], ['2.894220', '2.489128'], ['-2.562539', '2.884438'], ['3.491078', '-3.947487'], ['-2.565729', '-2.012114'], ['3.332948', '3.983102'], ['-1.616805', '3.573188'], ['2.280615', '-2.559444'], ['-2.651229', '-3.103198'], ['2.321395', '3.154987'], ['-1.685703', '2.939697'], ['3.031012', '-3.620252'], ['-4.599622', '-2.185829'], ['4.196223', '1.126677'], ['-2.133863', '3.093686'], ['4.668892', '-2.562705'], ['-2.793241', '-2.149706'], ['2.884105', '3.043438'], ['-2.967647', '2.848696'], ['4.479332', '-1.764772'], ['-4.905566', '-2.911070']]
[Finished in 0.2s]open(object,mode)函数的解释：
object:需要打开的文件名称
mode:打开的模式
w：只能操作写入 w+：可读可写
r：只能读取 r+：可读可写
a：向文件追加数据 a+：可读可追加
wb+：写入进制数据
值得注意的是：
w模式打开文件，如果文件中有数据，再次写入内容，会把原来数据的覆盖掉
a模式打开文件，如果文件中有数据，再次写入内容时，不会覆盖原来的数据，而是在其后添加数据
用open打开文件后，记得用close()关闭