I am working on a timeseries dataset which looks like this:

```
         DateTime         SomeVariable 
0   01/01 01:00:00          0.24244
1   01/01 02:00:00          0.84141
2   01/01 03:00:00          0.14144
3   01/01 04:00:00          0.74443
4   01/01 05:00:00          0.99999

```

The date is without year. Initially, the dtype of the DateTime is object and I am trying to change it to pandas datetime format. Since the date in my data is without year, on using:

```
df['DateTime'] = pd.to_datetime(df.DateTime)

```

I am getting the error `OutOfBoundsDatetime: Out of bounds nanosecond timestamp: 1-01-01 01:00:00`

I understand why I am getting the error (as it's not according to the pandas acceptable format), but what I want to know is how I can change the dtype from object to pandas datetime format without having year in my date. I would appreciate the hints.

EDIT 1:

Since, I got to know that I can't do it without having year in the data. So this is how I am trying to change the dtype:

```
df = pd.read_csv(some file location)
df['DateTime'] = pd.to_datetime('2018/'+df['DateTime'], format='%y%d/%m %H:%M:%S')
df.head()

```

On doing that, I am getting:

```
ValueError: time data '2018/ 01/01 01:00:00' doesn't match format specified.

```

EDIT 2:

Changing the format to `'%Y/%m/%d %H:%M:%S'`.
My data is hourly data, so it goes till 24h. I have only provided the demo data till 5h. 
I was getting the space on adding the year to the DateTime. In order to remove that, this is what I did:

```
df['DateTime'] = pd.to_datetime('2018/'+df['DateTime'][1:], format='%Y/%m/%d %H:%M:%S')

```

I am getting the following error for that:

```
ValueError: time data '2018/ 01/01  02:00:00' doesn't match format specified

```

On changing the format to `'%y/%m/%d %H:%M:%S'` with the same code, this is the error I get:

```
ValueError: time data '2018/ 01/01  02:00:00' does not match format '%y/%m/%d %H:%M:%S' (match)

```

The problem is because of the gap after the year but I am not able to get rid of it.

EDIT 3:

I am able to get rid of the space after adding the year, however I am still not able to change the dtype.

```
df['DateTime'] = pd.to_datetime('2018/'+df['DateTime'].str.strip(), format='%Y/%m/%d %H:%M:%S')

ValueError: time data '2018/01/01  01:00:00' doesn't match format specified

```

I noticed that there are 2 spaces between the date and the time in the error, however adding 2 spaces in the format doesn't help.

**EDIT 4 (Solution)**:

Removed all the multiple whitespaces. Still the format was not matching. The problem was because of the time format. The hours were from 1-24 in my data and pandas support 0-23. Simply changed the time 24:00:00 to 00:00:00 and it works perfectly now.