Question

我试图使用for循环将times_from_text_file数组中的字符串数组转换为日期时间，然后我想将这些日期时间映射到另一个名为temperature的数组，print false并返回温度数组的值。如果温度数组中的所有值都相同，那么唯一的时间就不会被绘制，只是真正打印。我遇到的问题是将我的times_from_text_file数组中的所有字符串时间转换为日期时间，这会导致下面的错误。

def values_equal_np_array(temp, time_created_index, time_modified_index, times_from_text_file):
    if (len(np.unique(temp)) == 1):
        return True
    else:
        #tells user the temps are not equal for a specified interval of time
        print ('False')

        plt.xlabel('Time')
        plt.ylabel('Temperature')
        plt.title('Time vs Temperature')        

        #specifying the beginning to end interval of temperature collection
        final_times = times_from_text_file[time_created_index:`time_modified_index]                  

        for i in range(len(final_times)):
            new_time = datetime.datetime.strptime(final_times, "%H:%M")
            datetimes.append(new_time)
            new_array[i] = new_time

        final_times = matplotlib.dates.date2num(new_time)
        matplotlib.pyplot.plot_date(new_array, temp)
        plt.show()

        #the values that appear in the non-uniform temperature array on display      
        return np.unique(temp)

#testing the function 
values_equal_np_array([1, 1, 1, 2, 3, 4], 3, 8, ['10:15','12:31','12:32','1:33', '12:34', '1:35', '2:36', '2:37', '3:38', '1:39'])

False

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-11-6151e84dc0c7> in <module>()
----> 1 values_equal_np_array([1, 1, 1, 2, 3, 4], 3, 8, ['10:15','12:31','12:32','1:33', '12:34', '1:35', '2:36', '2:37', '3:38', '1:39'])

<ipython-input-10-96555d9f1618> in values_equal_np_array(temp, time_created_index, time_modified_index, times_from_text_file)
     15 
     16         for i in range(len(final_times)):
---> 17             new_time = datetime.datetime.strptime(final_times, "%H:%M")
     18             datetimes.append(new_time)
     19             new_array[i] = new_time

TypeError: strptime() argument 1 must be str, not list

Answer 1

使用list comprehension：

new_times = [datetime.datetime.strptime(x, "%H:%M") for x in final_times]

将字符串数组转换为matplotlib的日期时间python

1 个答案: