Concatenate two numerical values to make a new column using pandas?

Question

I have two columns in my dataframe.

var1    var2
01       001

I would like to create a third column that joins them together:

Answer 1

Convert to both columns to string and then join both the columns to form the third column.

Code:

df['var1']=df['var1'].astype(str)
df['var2']=df['var2'].astype(str)
df['var3'] = df[['var1', 'var2']].apply(lambda x: ''.join(x), axis=1)