时间序列数据，例如我要2014-02-01对应的代码怎么写。数据如下，在R中是时间序列的格式
2014-01-10
-0.0406499670
2014-01-13
-0.0406780358
2014-01-14
0.0680208824
2014-01-15
-0.0057903666
2014-01-16
0.0274541541
2014-01-17
0.0097165922
2014-01-20
-0.0152357198
2014-01-21
0.0138432995
2014-01-22
0.0385541696
2014-01-23
0.0556843890
2014-01-24
0.0622715221
2014-01-27
0.0448272398
2014-01-28
0.0079206764
2014-01-29
0.0045875651
2014-01-30
-0.0215122367
2014-02-07
0.0133209644
2014-02-10
0.0848125731
2014-02-11
-0.0236363847
2014-02-12
-0.0260706339
2014-02-13
0.0707455562
2014-02-14
0.1000000765
2014-02-17
0.0817126818
2014-02-18
0.1000471606
2014-02-19
0.0468417931
2014-02-20
-0.0994806484
2014-02-21
-0.0361794454
2014-02-24
-0.0060059988
2014-02-25
-0.1002039974
2014-02-26
0.0615614443
2014-02-27
-0.0152923602
2014-02-28
0.0182039751
2014-03-03
0.0336512813
2014-03-04
-0.0432373275
2014-03-05
0.0079745145
2014-03-06
-0.0516851568
2014-03-07
-0.0272552069
2014-03-10
-0.0857633706
2014-03-11
0.0043809953
2014-03-12
0.0305042009
2014-03-13
0.0000000000
2014-03-14
0.0000000000
2014-03-17
0.0000000000
2014-03-18
0.0000000000
2014-03-19
0.0000000000
2014-03-20
0.0634443682
2014-03-21
-0.0187501660
2014-03-24
-0.0028922696
2014-03-25
-0.0220644455
2014-03-26
0.0409736521
2014-03-27
-0.0462063648
2014-03-28
-0.0424699429
2014-03-31
-0.0305997618
2014-04-01
0.0367267997
2014-04-02
-0.0161653232
2014-04-03
-0.0107360298
2014-04-04
0.0089368877
2014-04-08
0.0183608188
2014-04-09
0.0155313949
2014-04-10
0.0997584745
2014-04-11
0.0239314672
2014-04-14
-0.0266330820
2014-04-15
-0.0016749055
2014-04-16
-0.0106293041
2014-04-17
0.0169587622
2014-04-18
-0.0083379347
2014-04-21
-0.0639015389
2014-04-22
-0.0389192936
2014-04-23
-0.0348877235
2014-04-24
0.0006388874
2014-04-25
-0.0767712003
2014-04-28
-0.0020962655
2014-04-29
0.0154064808
2014-04-30
0.0062068315
2014-05-05
-0.0082247993