值错误：时间数据'12：00：01 AM'与使用time.strptime的格式'％I：％M：00％p'不匹配

Question

I'm a bit new to python so any help is greatly appreciated. Thanks in advance (and sorry for any mislabel).

I'm working on a csv file containing columns with Date, Time, CO, CO2 and CH4. What I want to achieve is to make a loop so that every time there is a time with zero seconds (ex: "12:00:00 AM", "3:05:00 PM" etc) it will take the data of that row and send it to a new text or csv file(this part is not included in the code). I imported the csv using pandas and used time.strptime to convert the string to readable time format.

Unfortunately since there is some data missing, I can't make a loop to gather every 60th data for this. I've also tried making a function using strptime but it also gives me a type error saying it must be a string and not a panda core series.

Importing the csv file:

data1 = pd.read_csv("prueba1.csv")
print(data1)

Where the output is:

         DATE         TIME     CO  CO2_dry  CH4_dry
0    3/4/2019  12:00:00 AM  0.352      420     1.99
1    3/4/2019  12:00:01 AM  0.352      420     1.99
2    3/4/2019  12:00:02 AM  0.352      420     1.99
3    3/4/2019  12:00:03 AM  0.366      420     1.99
4    3/4/2019  12:00:04 AM  0.366      420     1.99
5    3/4/2019  12:00:05 AM  0.366      421     1.99
6    3/4/2019  12:00:06 AM  0.369      421     1.99
7    3/4/2019  12:00:07 AM  0.369      421     1.99
8    3/4/2019  12:00:09 AM  0.354      421     1.99
9    3/4/2019  12:00:10 AM  0.354      421     1.99

And the code I'm using is

for i in data1["TIME"]:
        time.strptime(i,"%I:%M:%S %p")
        if time.strptime(i,"%I:%M:%S %p") == time.strptime(i,"%I:%M:00 %p"):
            print("Found a number!", i)
        else:
            print("Yikes")

The error message is:

Found a number! 12:00:00 AM

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-18-8b936d17df46> in <module>()
      2         time.strptime(i,"%I:%M:%S %p")
      3         #print(i)
----> 4         if time.strptime(i,"%I:%M:%S %p") == time.strptime(i,"%I:%M:00 %p"):
      5             print("Found a number!", i)
      6         else:

C:\Users\Diego\Anaconda3\lib\_strptime.py in _strptime_time(data_string, format)
    557     """Return a time struct based on the input string and the
    558     format string."""
--> 559     tt = _strptime(data_string, format)[0]
    560     return time.struct_time(tt[:time._STRUCT_TM_ITEMS])
    561 

C:\Users\Diego\Anaconda3\lib\_strptime.py in _strptime(data_string, format)
    360     if not found:
    361         raise ValueError("time data %r does not match format %r" %
--> 362                          (data_string, format))
    363     if len(data_string) != found.end():
    364         raise ValueError("unconverted data remains: %s" %

ValueError: time data '12:00:01 AM' does not match format '%I:%M:00 %p'

It returns the preceding output. I expected for it to return all time numbers matching the '%I:%M:00 %p' format, but only returned the first number. It seems odd to me that it stopped after it encountered the first number not matching the specified format.

Answer 1

If you want to skip errors, then you should use try and except

for i in data1["TIME"]:
        try:
           time.strptime(i,"%I:%M:%S %p")
           if time.strptime(i,"%I:%M:%S %p") == time.strptime(i,"%I:%M:00 %p"):
              print("Found a number!", i)
           else:
              print("Yikes")
        except ValueError:
              print("Ouch! Something failed")

Answer 2

You are doing it the long way. pd.to_datetime is both fast and convenient:

df['DATE'] = pd.to_datetime(df['DATE'])
df['TIME'] = pd.to_datetime(df['TIME']).dt.time

Of if your situation calls for a precise format:

df['DATE'] = pd.to_datetime(df['DATE'], format='%m/%d/%Y')
df['TIME'] = pd.to_datetime(df['TIME'], format='%I:%M:%S %p').dt.time

You can get the datetime format specifiers from strftime.org