python - Pandas: how to add an incremental value to a new column?

Question

I have a dataframe where I want to add a column id, for the first row I would like to start with a precise value (for example start_id = 1200) and for each row add 1 to the value of the previous id.

dataframe:

    x   
1   paris   
2   paris  
3   lyon  
4   lyon   
5   toulouse

Expected output:

    id     x      
1   1200   paris   
2   1201   paris  
3   1202   lyon  
4   1203   lyon   
5   1204   toulouse

I tried this but doesn't work:

df.insert(start_id, 'id', range(start_id, 1 + len(df)))

How can I do this ?

Answer 1

One way to do it with range() and len(df), So it will start from 1200 and add row's on id column incrementally

df['id'] = range(1200, 1200+len(df))