将文本文件中的日期列转换为浮点 [英] convert date column in a text file to float

问题描述

我有一个数据文件，该文件的第二列是日期，格式为"01/01/2007".我试图将此列转换为数字格式，以便可以将文本文件中的数据插入到mysql数据库中.尝试这样做时，我总是收到这些错误:

I have a data file with the 2nd column in the file being dates in the format '01/01/2007'. I am trying to convert this column into number format so that I can insert the data in the textfile into a mysql database. I keep getting these errors when I try to do so:

Traceback (most recent call last):
  File "C:/Python27/numpy", line 5, in <module>
    x = np.loadtxt(fname='xyz.txt', dtype=[('date', 'str', 12),('x','float')], converters={1:datestr2num}, delimiter=None, skiprows=0, usecols=None);
  File "C:\Python27\lib\site-packages\numpy\lib\npyio.py", line 713, in loadtxt
    X.append(tuple([conv(val) for (conv, val) in zip(converters, vals)]))
  File "C:/Python27/numpy", line 4, in datestr2num
    return datetime.datetime.strptime(s,'"%m/%d/%y"')
  File "C:\Python27\lib\_strptime.py", line 325, in _strptime
    (data_string, format))
ValueError: time data '"01/01/2007"' does not match format '"%m/%d/%y"'

有人可以帮我吗?这是我正在尝试的代码:

Can anyone please help me with this? Here is the code I am trying:

import numpy as np
import datetime
def datestr2num(s):
    return datetime.datetime.strptime(s,'"%m/%d/%y"')
x = np.loadtxt(fname='xyz.txt', dtype= 'float', converters={1:datestr2num}, delimiter=None, skiprows=0, usecols=None);
print x;

推荐答案

'%y'是两位数的年份(例如'14')；您有四位数的年份(例如'2014')，因此应该使用'%Y'-请参见文档.

'%y' is for two-digit years (e.g. '14'); you have four-digit years (e.g. '2014') so should be using '%Y' - see the documentation.

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