I am trying to read in a dataset called df1, but it does not work

import pandas as pd
df1=pd.read_csv("https://raw.githubusercontent.com/tuyenhavan/Statistics/Dataset/World_Life_Expectancy.csv",sep=";")

df1.head()

Here are huge errors from the above code, but this is the most relevant

UnicodeDecodeError: 'utf-8' codec can't decode byte 0x92 in position 18: invalid start byte

The data is indeed not encoded as UTF-8; everything is ASCII except for that single 0x92 byte:

b'Korea, Dem. People\x92s Rep.'

Decode it as Windows codepage 1252 instead, where 0x92 is a fancy quote, :

df1 = pd.read_csv("https://raw.githubusercontent.com/tuyenhavan/Statistics/Dataset/World_Life_Expectancy.csv",
                  sep=";", encoding='cp1252')

Demo:

>>> import pandas as pd
>>> df1 = pd.read_csv("https://raw.githubusercontent.com/tuyenhavan/Statistics/Dataset/World_Life_Expectancy.csv",
...                   sep=";", encoding='cp1252')
>>> df1.head()
                   2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  \
0     Afghanistan  55.1  55.5  55.9  56.2  56.6  57.0  57.4  57.8  58.2  58.6
1         Albania  74.3  74.7  75.2  75.5  75.8  76.1  76.3  76.5  76.7  76.8
2         Algeria  70.2  70.6  71.0  71.4  71.8  72.2  72.6  72.9  73.2  73.5
3  American Samoa    ..    ..    ..    ..    ..    ..    ..    ..    ..    ..
4         Andorra    ..    ..    ..    ..    ..    ..    ..    ..    ..    ..

   2010  2011  2012  2013  Unnamed: 15  2014  2015
0  59.0  59.3  59.7  60.0          NaN  60.4  60.7
1  77.0  77.2  77.4  77.6          NaN  77.8  78.0
2  73.8  74.1  74.3  74.6          NaN  74.8  75.0
3    ..    ..    ..    ..          NaN    ..    ..
4    ..    ..    ..    ..          NaN    ..    ..

I note however, that Pandas seems to take the HTTP headers at face value too and produces a Mojibake when you load your data from a URL. When I save the data directly to disk, then load it with pd.read_csv() the data is correctly decoded, but loading from the URL produces re-coded data:

>>> df1[' '][102]
'Korea, Dem. People’s Rep.'
>>> df1[' '][102].encode('cp1252').decode('utf8')
'Korea, Dem. People’s Rep.'

This is a known bug in Pandas. You can work around this by using urllib.request to load the URL and pass that to pd.read_csv() instead:

>>> import urllib.request
>>> with urllib.request.urlopen("https://raw.githubusercontent.com/tuyenhavan/Statistics/Dataset/World_Life_Expectancy.csv") as resp:
...     df1 = pd.read_csv(resp, sep=";", encoding='cp1252')
...
>>> df1[' '][102]
'Korea, Dem. People’s Rep.'

It turned out that the csv created in mac os is being parsed on a windows machine, I got the UnicodeDecodeError.
To get rid of this error, try passing argument encoding=’mac-roman’ to read_csv method of pandas library.

import pandas as pd
df1=pd.read_csv("https://raw.githubusercontent.com/tuyenhavan/Statistics/Dataset/World_Life_Expectancy.csv",sep=";", encoding='mac_roman')
df1.head()

Output:

    2000    2001    2002    2003    2004    2005    2006    2007    2008    2009    2010    2011    2012    2013    Unnamed: 15 2014    2015
0   Afghanistan 55.1    55.5    55.9    56.2    56.6    57.0    57.4    57.8    58.2    58.6    59.0    59.3    59.7    60.0    NaN 60.4    60.7
1   Albania 74.3    74.7    75.2    75.5    75.8    76.1    76.3    76.5    76.7    76.8    77.0    77.2    77.4    77.6    NaN 77.8    78.0
2   Algeria 70.2    70.6    71.0    71.4    71.8    72.2    72.6    72.9    73.2    73.5    73.8    74.1    74.3    74.6    NaN 74.8    75.0
3   American Samoa  ..  ..  ..  ..  ..  ..  ..  ..  ..  ..  ..  ..  ..  ..  NaN ..  ..
4   Andorra ..  ..  ..  ..  ..  ..  ..  ..  ..  ..  ..  ..  ..  ..  NaN ..  ..

This problem occur because of some unknown characters in your file.
for example, In your file with utf-8 encoding, there were some character in windows 1250.
you should remove or replace this characters to solve your problems

This works

df = pd.read_csv(inputfile, engine="python")