Databases
StackOverflow2013
Postsdbo
POPandas: how to change all the values of a column?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POPandas: how to change all the values of a column?
    primarykey
    data
    text
    <p>I have a data frame with a column called <code>"Date"</code> and want all the values from this column to have the same value (the year only). Example:</p> <pre><code>City Date Paris 01/04/2004 Lisbon 01/09/2004 Madrid 2004 Pekin 31/2004 </code></pre> <p>What I want is:</p> <pre><code>City Date Paris 2004 Lisbon 2004 Madrid 2004 Pekin 2004 </code></pre> <p>Here is my code:</p> <pre><code>fr61_70xls = pd.ExcelFile('AMADEUS FRANCE 1961-1970.xlsx') #Here we import the individual sheets and clean the sheets years=(['1961','1962','1963','1964','1965','1966','1967','1968','1969','1970']) fr={} header=(['City','Country','NACE','Cons','Last_year','Op_Rev_EUR_Last_avail_yr','BvD_Indep_Indic','GUO_Name','Legal_status','Date_of_incorporation','Legal_status_date']) for year in years: # save every sheet in variable fr['1961'], fr['1962'] and so on fr[year]=fr61_70xls.parse(year,header=0,parse_cols=10) fr[year].columns=header # drop the entire Legal status date column fr[year]=fr[year].drop(['Legal_status_date','Date_of_incorporation'],axis=1) # drop every row where GUO Name is empty fr[year]=fr[year].dropna(axis=0,how='all',subset=[['GUO_Name']]) fr[year]=fr[year].set_index(['GUO_Name','Date_of_incorporation']) </code></pre> <p><em>It happens that in my DataFrames, called for example <code>fr['1961']</code> the values of <code>Date_of_incorporation</code> can be anything (strings, integer, and so on), so maybe it would be best to completely erase this column and then attach another column with only the year to the DataFrames?</em></p>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. USAndy Hayden
    1. USbrodrigues
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POPandas: how to change all the values of a column?
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POPandas: how to change all the values of a column?
      1. UScantdutchthis
      1. VTFavorite
    3. VO
      singulars
      1. POPandas: how to change all the values of a column?
      1. This table or related slice is empty.
      1. VTUpMod
    1. COAre the dates just strings?
      singulars
      1. POPandas: how to change all the values of a column?
      1. USAndy Hayden
    2. COStrings and numbers depending on whether there is only the year (like for Madrid in the example), or whether there is also the month and day (like for Pekin and Paris).
      singulars
      1. POPandas: how to change all the values of a column?
      1. USbrodrigues
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload