import pandas as pd
pd.set_option("display.max_rows", 6)

DataFrame 

pd.DataFrame({Column1: [Value1.1, Value2.1],
              Column2: [Value1.2, Value2.2]},
            index=["Row1", "Row2"])

DataFrame = table as Excel

pd.DataFrame({"Column_1": ["Value_1.1", "Value_2.1"],
              "Column_2": ["Value_1.2", "Value_2.2"]},
             index=["Row_1", "Row_2"])
Column_1 Column_2
Row_1 Value_1.1 Value_1.2
Row_2 Value_2.1 Value_2.2 
pd.DataFrame({"Apples": [35, 41], 
              "Bananas": [21, 34]},
             index=["2017 Sales", "2018 Sales"])
Apples Bananas
2017 Sales 35 21
2018 Sales 41 34

Series 

pd.Series([Value1, Value2, Value3],
          index=["Row1", "Row2", "Row3"],
          name="nameSerie")

Series = list

pd.Series(["Value_1", "Value_2", "Value_3"],
          index=["Row1", "Row2", "Row3"],
          name="nameSerie")

Row1    Value_1
Row2    Value_2
Row3    Value_3
Name: nameSerie, dtype: object
pd.Series(["4 cups", "1 cup", "2 large", "1 can"],
          index=["Flour", "Milk", "Eggs", "Spam"],
          name="Dinner")

Flour     4 cups
Milk       1 cup
Eggs     2 large
Spam       1 can
Name: Dinner, dtype: object

Reading 

pd.read_csv("path", index_col=0)

Put the option "index_col=0" if you want to use the index inside the csv (in first column)

wines = pd.read_csv("./src/winemag-data-130k-v2.csv", index_col=0)

wines.shape

(129971, 13)
wines.head()
country description designation points price province region_1 region_2 taster_name taster_twitter_handle title variety winery
0 Italy Aromas include tropical fruit, broom, brimston... Vulkà Bianco 87 NaN Sicily & Sardinia Etna NaN Kerin O’Keefe @kerinokeefe Nicosia 2013 Vulkà Bianco (Etna) White Blend Nicosia
1 Portugal This is ripe and fruity, a wine that is smooth... Avidagos 87 15.0 Douro NaN NaN Roger Voss @vossroger Quinta dos Avidagos 2011 Avidagos Red (Douro) Portuguese Red Quinta dos Avidagos
2 US Tart and snappy, the flavors of lime flesh and... NaN 87 14.0 Oregon Willamette Valley Willamette Valley Paul Gregutt @paulgwine Rainstorm 2013 Pinot Gris (Willamette Valley) Pinot Gris Rainstorm
3 US Pineapple rind, lemon pith and orange blossom ... Reserve Late Harvest 87 13.0 Michigan Lake Michigan Shore NaN Alexander Peartree NaN St. Julian 2013 Reserve Late Harvest Riesling ... Riesling St. Julian
4 US Much like the regular bottling from 2012, this... Vintner's Reserve Wild Child Block 87 65.0 Oregon Willamette Valley Willamette Valley Paul Gregutt @paulgwine Sweet Cheeks 2012 Vintner's Reserve Wild Child... Pinot Noir Sweet Cheeks

Index with iloc (numerical position) 

data.iloc[row, column]

":" minds everithing

iloc uses the Python stdlib indexing scheme, where the first element of the range is included and the last one excluded.

Warning: with iloc : [0:10] => 0,...,9 
wines.iloc[0]

country                                                    Italy
description    Aromas include tropical fruit, broom, brimston...
designation                                         Vulkà Bianco
                                     ...                        
title                          Nicosia 2013 Vulkà Bianco  (Etna)
variety                                              White Blend
winery                                                   Nicosia
Name: 0, Length: 13, dtype: object
wines.iloc[:, 0]

0            Italy
1         Portugal
2               US
            ...   
129968      France
129969      France
129970      France
Name: country, Length: 129971, dtype: object
wines.iloc[:3, 0]

0       Italy
1    Portugal
2          US
Name: country, dtype: object
wines.iloc[1:3, 0]

1    Portugal
2          US
Name: country, dtype: object
wines.iloc[[0, 1, 2], 0]

0       Italy
1    Portugal
2          US
Name: country, dtype: object
wines.iloc[-5:]
country description designation points price province region_1 region_2 taster_name taster_twitter_handle title variety winery
129966 Germany Notes of honeysuckle and cantaloupe sweeten th... Brauneberger Juffer-Sonnenuhr Spätlese 90 28.0 Mosel NaN NaN Anna Lee C. Iijima NaN Dr. H. Thanisch (Erben Müller-Burggraef) 2013 ... Riesling Dr. H. Thanisch (Erben Müller-Burggraef)
129967 US Citation is given as much as a decade of bottl... NaN 90 75.0 Oregon Oregon Oregon Other Paul Gregutt @paulgwine Citation 2004 Pinot Noir (Oregon) Pinot Noir Citation
129968 France Well-drained gravel soil gives this wine its c... Kritt 90 30.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Gresser 2013 Kritt Gewurztraminer (Als... Gewürztraminer Domaine Gresser
129969 France A dry style of Pinot Gris, this is crisp with ... NaN 90 32.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Marcel Deiss 2012 Pinot Gris (Alsace) Pinot Gris Domaine Marcel Deiss
129970 France Big, rich and off-dry, this is powered by inte... Lieu-dit Harth Cuvée Caroline 90 21.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Schoffit 2012 Lieu-dit Harth Cuvée Car... Gewürztraminer Domaine Schoffit

Index with loc (label_based position) 

data.loc[row, column]

loc indexes inclusively. So 0:10 will select entries 0,...,10.

Warning: with loc : [0:10] => 0,...,10 
wines.loc[:, "points"]

0         87
1         87
2         87
          ..
129968    90
129969    90
129970    90
Name: points, Length: 129971, dtype: int64
wines.loc[0:9,["country", "variety"]]
country variety
0 Italy White Blend
1 Portugal Portuguese Red
2 US Pinot Gris
... ... ...
7 France Gewürztraminer
8 Germany Gewürztraminer
9 France Pinot Gris

10 rows × 2 columns

wines.loc[(wines.country == 'Italy') & (wines.points >= 90)]
country description designation points price province region_1 region_2 taster_name taster_twitter_handle title variety winery
120 Italy Slightly backward, particularly given the vint... Bricco Rocche Prapó 92 70.0 Piedmont Barolo NaN NaN NaN Ceretto 2003 Bricco Rocche Prapó (Barolo) Nebbiolo Ceretto
130 Italy At the first it was quite muted and subdued, b... Bricco Rocche Brunate 91 70.0 Piedmont Barolo NaN NaN NaN Ceretto 2003 Bricco Rocche Brunate (Barolo) Nebbiolo Ceretto
133 Italy Einaudi's wines have been improving lately, an... NaN 91 68.0 Piedmont Barolo NaN NaN NaN Poderi Luigi Einaudi 2003 Barolo Nebbiolo Poderi Luigi Einaudi
... ... ... ... ... ... ... ... ... ... ... ... ... ...
129947 Italy A blend of 65% Cabernet Sauvignon, 30% Merlot ... Symposio 90 20.0 Sicily & Sardinia Terre Siciliane NaN Kerin O’Keefe @kerinokeefe Feudo Principi di Butera 2012 Symposio Red (Te... Red Blend Feudo Principi di Butera
129961 Italy Intense aromas of wild cherry, baking spice, t... NaN 90 30.0 Sicily & Sardinia Sicilia NaN Kerin O’Keefe @kerinokeefe COS 2013 Frappato (Sicilia) Frappato COS
129962 Italy Blackberry, cassis, grilled herb and toasted a... Sàgana Tenuta San Giacomo 90 40.0 Sicily & Sardinia Sicilia NaN Kerin O’Keefe @kerinokeefe Cusumano 2012 Sàgana Tenuta San Giacomo Nero d... Nero d'Avola Cusumano

6648 rows × 13 columns

wines.loc[(wines.country == 'Italy') | (wines.points >= 90)]
country description designation points price province region_1 region_2 taster_name taster_twitter_handle title variety winery
0 Italy Aromas include tropical fruit, broom, brimston... Vulkà Bianco 87 NaN Sicily & Sardinia Etna NaN Kerin O’Keefe @kerinokeefe Nicosia 2013 Vulkà Bianco (Etna) White Blend Nicosia
6 Italy Here's a bright, informal red that opens with ... Belsito 87 16.0 Sicily & Sardinia Vittoria NaN Kerin O’Keefe @kerinokeefe Terre di Giurfo 2013 Belsito Frappato (Vittoria) Frappato Terre di Giurfo
13 Italy This is dominated by oak and oak-driven aromas... Rosso 87 NaN Sicily & Sardinia Etna NaN Kerin O’Keefe @kerinokeefe Masseria Setteporte 2012 Rosso (Etna) Nerello Mascalese Masseria Setteporte
... ... ... ... ... ... ... ... ... ... ... ... ... ...
129968 France Well-drained gravel soil gives this wine its c... Kritt 90 30.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Gresser 2013 Kritt Gewurztraminer (Als... Gewürztraminer Domaine Gresser
129969 France A dry style of Pinot Gris, this is crisp with ... NaN 90 32.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Marcel Deiss 2012 Pinot Gris (Alsace) Pinot Gris Domaine Marcel Deiss
129970 France Big, rich and off-dry, this is powered by inte... Lieu-dit Harth Cuvée Caroline 90 21.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Schoffit 2012 Lieu-dit Harth Cuvée Car... Gewürztraminer Domaine Schoffit

61937 rows × 13 columns

wines.loc[wines.country.isin(['Italy', 'France'])]
country description designation points price province region_1 region_2 taster_name taster_twitter_handle title variety winery
0 Italy Aromas include tropical fruit, broom, brimston... Vulkà Bianco 87 NaN Sicily & Sardinia Etna NaN Kerin O’Keefe @kerinokeefe Nicosia 2013 Vulkà Bianco (Etna) White Blend Nicosia
6 Italy Here's a bright, informal red that opens with ... Belsito 87 16.0 Sicily & Sardinia Vittoria NaN Kerin O’Keefe @kerinokeefe Terre di Giurfo 2013 Belsito Frappato (Vittoria) Frappato Terre di Giurfo
7 France This dry and restrained wine offers spice in p... NaN 87 24.0 Alsace Alsace NaN Roger Voss @vossroger Trimbach 2012 Gewurztraminer (Alsace) Gewürztraminer Trimbach
... ... ... ... ... ... ... ... ... ... ... ... ... ...
129968 France Well-drained gravel soil gives this wine its c... Kritt 90 30.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Gresser 2013 Kritt Gewurztraminer (Als... Gewürztraminer Domaine Gresser
129969 France A dry style of Pinot Gris, this is crisp with ... NaN 90 32.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Marcel Deiss 2012 Pinot Gris (Alsace) Pinot Gris Domaine Marcel Deiss
129970 France Big, rich and off-dry, this is powered by inte... Lieu-dit Harth Cuvée Caroline 90 21.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Schoffit 2012 Lieu-dit Harth Cuvée Car... Gewürztraminer Domaine Schoffit

41633 rows × 13 columns

wines.loc[wines.price.notnull()]
country description designation points price province region_1 region_2 taster_name taster_twitter_handle title variety winery
1 Portugal This is ripe and fruity, a wine that is smooth... Avidagos 87 15.0 Douro NaN NaN Roger Voss @vossroger Quinta dos Avidagos 2011 Avidagos Red (Douro) Portuguese Red Quinta dos Avidagos
2 US Tart and snappy, the flavors of lime flesh and... NaN 87 14.0 Oregon Willamette Valley Willamette Valley Paul Gregutt @paulgwine Rainstorm 2013 Pinot Gris (Willamette Valley) Pinot Gris Rainstorm
3 US Pineapple rind, lemon pith and orange blossom ... Reserve Late Harvest 87 13.0 Michigan Lake Michigan Shore NaN Alexander Peartree NaN St. Julian 2013 Reserve Late Harvest Riesling ... Riesling St. Julian
... ... ... ... ... ... ... ... ... ... ... ... ... ...
129968 France Well-drained gravel soil gives this wine its c... Kritt 90 30.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Gresser 2013 Kritt Gewurztraminer (Als... Gewürztraminer Domaine Gresser
129969 France A dry style of Pinot Gris, this is crisp with ... NaN 90 32.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Marcel Deiss 2012 Pinot Gris (Alsace) Pinot Gris Domaine Marcel Deiss
129970 France Big, rich and off-dry, this is powered by inte... Lieu-dit Harth Cuvée Caroline 90 21.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Schoffit 2012 Lieu-dit Harth Cuvée Car... Gewürztraminer Domaine Schoffit

120975 rows × 13 columns

wines.loc[wines.price.isnull()]
country description designation points price province region_1 region_2 taster_name taster_twitter_handle title variety winery
0 Italy Aromas include tropical fruit, broom, brimston... Vulkà Bianco 87 NaN Sicily & Sardinia Etna NaN Kerin O’Keefe @kerinokeefe Nicosia 2013 Vulkà Bianco (Etna) White Blend Nicosia
13 Italy This is dominated by oak and oak-driven aromas... Rosso 87 NaN Sicily & Sardinia Etna NaN Kerin O’Keefe @kerinokeefe Masseria Setteporte 2012 Rosso (Etna) Nerello Mascalese Masseria Setteporte
30 France Red cherry fruit comes laced with light tannin... Nouveau 86 NaN Beaujolais Beaujolais-Villages NaN Roger Voss @vossroger Domaine de la Madone 2012 Nouveau (Beaujolais... Gamay Domaine de la Madone
... ... ... ... ... ... ... ... ... ... ... ... ... ...
129863 Portugal This mature wine that has 50% Touriga Nacional... Reserva 90 NaN Dão NaN NaN Roger Voss @vossroger Seacampo 2011 Reserva Red (Dão) Portuguese Red Seacampo
129893 Italy Aromas of passion fruit, hay and a vegetal not... Corte Menini 91 NaN Veneto Soave Classico NaN Kerin O’Keefe @kerinokeefe Le Mandolare 2015 Corte Menini (Soave Classico) Garganega Le Mandolare
129964 France Initially quite muted, this wine slowly develo... Domaine Saint-Rémy Herrenweg 90 NaN Alsace Alsace NaN Roger Voss @vossroger Domaine Ehrhart 2013 Domaine Saint-Rémy Herren... Gewürztraminer Domaine Ehrhart

8996 rows × 13 columns

Summary functions 

wines.points.describe()

count    129971.000000
mean         88.447138
std           3.039730
             ...      
50%          88.000000
75%          91.000000
max         100.000000
Name: points, Length: 8, dtype: float64
wines.taster_name.describe()

count         103727
unique            19
top       Roger Voss
freq           25514
Name: taster_name, dtype: object
wines.points.mean()

88.44713820775404
wines.points.median()

88.0
wines.taster_name.unique()

array(['Kerin O’Keefe', 'Roger Voss', 'Paul Gregutt',
       'Alexander Peartree', 'Michael Schachner', 'Anna Lee C. Iijima',
       'Virginie Boone', 'Matt Kettmann', nan, 'Sean P. Sullivan',
       'Jim Gordon', 'Joe Czerwinski', 'Anne Krebiehl\xa0MW',
       'Lauren Buzzeo', 'Mike DeSimone', 'Jeff Jenssen',
       'Susan Kostrzewa', 'Carrie Dykes', 'Fiona Adams',
       'Christina Pickard'], dtype=object)
wines.taster_name.value_counts()

Roger Voss           25514
Michael Schachner    15134
Kerin O’Keefe        10776
                     ...  
Carrie Dykes           139
Fiona Adams             27
Christina Pickard        6
Name: taster_name, Length: 19, dtype: int64

Maps 

mySeries.map(lambda p: function(p))

myDataFrame.apply(nameFunctionOnRow, axis="columns")

myDataFrame.apply(nameFunctionOnColumns, axis="index") (by default)

Note: map() and apply() return new, transformed Series and DataFrames, respectively. They don’t modify the original data they’re called on. 
review_points_mean = wines.points.mean()
wines.points.map(lambda p: p - review_points_mean)

0        -1.447138
1        -1.447138
2        -1.447138
            ...   
129968    1.552862
129969    1.552862
129970    1.552862
Name: points, Length: 129971, dtype: float64
review_points_mean = wines.points.mean()
wines.points - review_points_mean

0        -1.447138
1        -1.447138
2        -1.447138
            ...   
129968    1.552862
129969    1.552862
129970    1.552862
Name: points, Length: 129971, dtype: float64
def remean_points(row):
    row.points = row.points - review_points_mean
    return row

wines.apply(remean_points, axis='columns')
country description designation points price province region_1 region_2 taster_name taster_twitter_handle title variety winery
0 Italy Aromas include tropical fruit, broom, brimston... Vulkà Bianco -1.447138 NaN Sicily & Sardinia Etna NaN Kerin O’Keefe @kerinokeefe Nicosia 2013 Vulkà Bianco (Etna) White Blend Nicosia
1 Portugal This is ripe and fruity, a wine that is smooth... Avidagos -1.447138 15.0 Douro NaN NaN Roger Voss @vossroger Quinta dos Avidagos 2011 Avidagos Red (Douro) Portuguese Red Quinta dos Avidagos
2 US Tart and snappy, the flavors of lime flesh and... NaN -1.447138 14.0 Oregon Willamette Valley Willamette Valley Paul Gregutt @paulgwine Rainstorm 2013 Pinot Gris (Willamette Valley) Pinot Gris Rainstorm
... ... ... ... ... ... ... ... ... ... ... ... ... ...
129968 France Well-drained gravel soil gives this wine its c... Kritt 1.552862 30.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Gresser 2013 Kritt Gewurztraminer (Als... Gewürztraminer Domaine Gresser
129969 France A dry style of Pinot Gris, this is crisp with ... NaN 1.552862 32.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Marcel Deiss 2012 Pinot Gris (Alsace) Pinot Gris Domaine Marcel Deiss
129970 France Big, rich and off-dry, this is powered by inte... Lieu-dit Harth Cuvée Caroline 1.552862 21.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Schoffit 2012 Lieu-dit Harth Cuvée Car... Gewürztraminer Domaine Schoffit

129971 rows × 13 columns

# index of the bet bargain
bidx = (wines.points / wines.price).idxmax()
bargain_wine = wines.title.iloc[bidx]
bargain_wine

'Bandit NV Merlot (California)'
def nb_stars(row):
    if row.country == "Canada":
        return 3
    elif row.points >= 95:
        return 3
    elif row.points >= 85:
        return 2
    else:
        return 1
        
star_ratings = wines.apply(nb_stars, axis="columns")

print(star_ratings)

0         2
1         2
2         2
         ..
129968    2
129969    2
129970    2
Length: 129971, dtype: int64

nb_tropical = sum(wines.description.map(lambda p: "tropical" in p))

nb_fruity = sum(wines.description.map(lambda p: "fruity" in p))

descriptor_counts = pd.Series([nb_tropical, 
                               nb_fruity], 
                              index=['tropical', 'fruity'])

print(descriptor_counts)

tropical    3607
fruity      9090
dtype: int64

GroupBy 

wines.points.value_counts()

88     17207
87     16933
90     15410
       ...  
98        77
99        33
100       19
Name: points, Length: 21, dtype: int64
wines.groupby('points').points.count()

points
80      397
81      692
82     1836
       ... 
98       77
99       33
100      19
Name: points, Length: 21, dtype: int64
wines.groupby('points').price.min()

points
80      5.0
81      5.0
82      4.0
       ... 
98     50.0
99     44.0
100    80.0
Name: price, Length: 21, dtype: float64
wines.groupby('points').price.mean().round(1)

points
80      16.4
81      17.2
82      18.9
       ...  
98     245.5
99     284.2
100    485.9
Name: price, Length: 21, dtype: float64
wines.groupby('winery').apply(lambda df: df.title.iloc[0])

winery
1+1=3                                     1+1=3 NV Rosé Sparkling (Cava)
10 Knots                            10 Knots 2010 Viognier (Paso Robles)
100 Percent Wine              100 Percent Wine 2015 Moscato (California)
                                             ...                        
Ökonomierat Rebholz    Ökonomierat Rebholz 2007 Von Rotliegenden Spät...
àMaurice               àMaurice 2013 Fred Estate Syrah (Walla Walla V...
Štoka                                    Štoka 2009 Izbrani Teran (Kras)
Length: 16757, dtype: object
wines.groupby(['country', 'province']).apply(lambda df: df.loc[df.points.idxmax()])
country description designation points price province region_1 region_2 taster_name taster_twitter_handle title variety winery
country province
Argentina Mendoza Province Argentina If the color doesn't tell the full story, the ... Nicasia Vineyard 97 120.0 Mendoza Province Mendoza NaN Michael Schachner @wineschach Bodega Catena Zapata 2006 Nicasia Vineyard Mal... Malbec Bodega Catena Zapata
Other Argentina Take note, this could be the best wine Colomé ... Reserva 95 90.0 Other Salta NaN Michael Schachner @wineschach Colomé 2010 Reserva Malbec (Salta) Malbec Colomé
Armenia Armenia Armenia Deep salmon in color, this wine offers a bouqu... Estate Bottled 88 15.0 Armenia NaN NaN Mike DeSimone @worldwineguys Van Ardi 2015 Estate Bottled Rosé (Armenia) Rosé Van Ardi
... ... ... ... ... ... ... ... ... ... ... ... ... ... ...
Uruguay Progreso Uruguay Rusty in color but deep and complex in nature,... Etxe Oneko Fortified Sweet Red 90 46.0 Progreso NaN NaN Michael Schachner @wineschach Pisano 2007 Etxe Oneko Fortified Sweet Red Tan... Tannat Pisano
San Jose Uruguay Baked, sweet, heavy aromas turn earthy with ti... El Preciado Gran Reserva 87 50.0 San Jose NaN NaN Michael Schachner @wineschach Castillo Viejo 2005 El Preciado Gran Reserva R... Red Blend Castillo Viejo
Uruguay Uruguay Cherry and berry aromas are ripe, healthy and ... Blend 002 Limited Edition 91 22.0 Uruguay NaN NaN Michael Schachner @wineschach Narbona NV Blend 002 Limited Edition Tannat-Ca... Tannat-Cabernet Franc Narbona

425 rows × 13 columns

wines.groupby(['country']).price.agg([len, min, max])
len min max
country
Argentina 3800.0 4.0 230.0
Armenia 2.0 14.0 15.0
Australia 2329.0 5.0 850.0
... ... ... ...
US 54504.0 4.0 2013.0
Ukraine 14.0 6.0 13.0
Uruguay 109.0 10.0 130.0

43 rows × 3 columns

countries_reviewed = wines.groupby(['country', 'province']).description.agg([len])
countries_reviewed
len
country province
Argentina Mendoza Province 3264
Other 536
Armenia Armenia 2
... ... ...
Uruguay Progreso 11
San Jose 3
Uruguay 24

425 rows × 1 columns

mi = countries_reviewed.index
type(mi)

pandas.core.indexes.multi.MultiIndex
countries_reviewed.reset_index()
country province len
0 Argentina Mendoza Province 3264
1 Argentina Other 536
2 Armenia Armenia 2
... ... ... ...
422 Uruguay Progreso 11
423 Uruguay San Jose 3
424 Uruguay Uruguay 24

425 rows × 3 columns

Sorting 

myDataFrame.sort_values(by="nameColumn")  # ascending=True by default

myDataFrame.sort_values(by="nameColumn", ascending=False)

myDataFrame.sort_values(by=["nameColumn1", "nameColumn2"])

myDataFrame.sort_index()
countries_reviewed = countries_reviewed.reset_index()
countries_reviewed.sort_values(by='len')
country province len
179 Greece Muscat of Kefallonian 1
192 Greece Sterea Ellada 1
194 Greece Thraki 1
... ... ... ...
118 France Bordeaux 5941
415 US Washington 8639
392 US California 36247

425 rows × 3 columns

countries_reviewed.sort_values(by='len', ascending=False)
country province len
392 US California 36247
415 US Washington 8639
118 France Bordeaux 5941
... ... ... ...
357 South Africa Piekenierskloof 1
63 Chile Coelemu 1
149 Greece Beotia 1

425 rows × 3 columns

countries_reviewed.sort_index()
country province len
0 Argentina Mendoza Province 3264
1 Argentina Other 536
2 Armenia Armenia 2
... ... ... ...
422 Uruguay Progreso 11
423 Uruguay San Jose 3
424 Uruguay Uruguay 24

425 rows × 3 columns

countries_reviewed.sort_values(by=['country', 'len'])
country province len
1 Argentina Other 536
0 Argentina Mendoza Province 3264
2 Armenia Armenia 2
... ... ... ...
420 Uruguay Juanico 12
424 Uruguay Uruguay 24
419 Uruguay Canelones 43

425 rows × 3 columns

Data Types 

myDataFrameOrSeries.nameColumn.dtype

myDataFrameOrSeries.index.dtype

myDataFrameOrSeries.dtypes

myDataFrameOrSeries.nameColumn.astype("nameOfType")
wines
country description designation points price province region_1 region_2 taster_name taster_twitter_handle title variety winery
0 Italy Aromas include tropical fruit, broom, brimston... Vulkà Bianco 87 NaN Sicily & Sardinia Etna NaN Kerin O’Keefe @kerinokeefe Nicosia 2013 Vulkà Bianco (Etna) White Blend Nicosia
1 Portugal This is ripe and fruity, a wine that is smooth... Avidagos 87 15.0 Douro NaN NaN Roger Voss @vossroger Quinta dos Avidagos 2011 Avidagos Red (Douro) Portuguese Red Quinta dos Avidagos
2 US Tart and snappy, the flavors of lime flesh and... NaN 87 14.0 Oregon Willamette Valley Willamette Valley Paul Gregutt @paulgwine Rainstorm 2013 Pinot Gris (Willamette Valley) Pinot Gris Rainstorm
... ... ... ... ... ... ... ... ... ... ... ... ... ...
129968 France Well-drained gravel soil gives this wine its c... Kritt 90 30.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Gresser 2013 Kritt Gewurztraminer (Als... Gewürztraminer Domaine Gresser
129969 France A dry style of Pinot Gris, this is crisp with ... NaN 90 32.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Marcel Deiss 2012 Pinot Gris (Alsace) Pinot Gris Domaine Marcel Deiss
129970 France Big, rich and off-dry, this is powered by inte... Lieu-dit Harth Cuvée Caroline 90 21.0 Alsace Alsace NaN Roger Voss @vossroger Domaine Schoffit 2012 Lieu-dit Harth Cuvée Car... Gewürztraminer Domaine Schoffit

129971 rows × 13 columns

wines.index.dtype

dtype('int64')
wines.price.dtype

dtype('float64')

Missing Data

Important: Entries missing values are given the value NaN, short for "Not a Number". For technical reasons these NaN values are always of the float64 dtype.
--- 
myDataFrameOrSeries[pd.isnull(myDataFrameOrSeries.nameColumn)]

myDataFrameOrSeries[pd.notnull(myDataFrameOrSeries.nameColumn)]

myDataFrameOrSeries.nameColumn.fillna(value)

myDataFrameOrSeries.nameColumn.replace(oldValue, newValue)
wines[pd.isnull(wines.country)]
country description designation points price province region_1 region_2 taster_name taster_twitter_handle title variety winery
913 NaN Amber in color, this wine has aromas of peach ... Asureti Valley 87 30.0 NaN NaN NaN Mike DeSimone @worldwineguys Gotsa Family Wines 2014 Asureti Valley Chinuri Chinuri Gotsa Family Wines
3131 NaN Soft, fruity and juicy, this is a pleasant, si... Partager 83 NaN NaN NaN NaN Roger Voss @vossroger Barton & Guestier NV Partager Red Red Blend Barton & Guestier
4243 NaN Violet-red in color, this semisweet wine has a... Red Naturally Semi-Sweet 88 18.0 NaN NaN NaN Mike DeSimone @worldwineguys Kakhetia Traditional Winemaking 2012 Red Natur... Ojaleshi Kakhetia Traditional Winemaking
... ... ... ... ... ... ... ... ... ... ... ... ... ...
129408 NaN El Capricho is one of Uruguay's more consisten... Reserve 89 22.0 NaN NaN NaN Michael Schachner @wineschach El Capricho 2015 Reserve Tempranillo Tempranillo El Capricho
129590 NaN A blend of 60% Syrah, 30% Cabernet Sauvignon a... Shah 90 30.0 NaN NaN NaN Mike DeSimone @worldwineguys Büyülübağ 2012 Shah Red Red Blend Büyülübağ
129900 NaN This wine offers a delightful bouquet of black... NaN 91 32.0 NaN NaN NaN Mike DeSimone @worldwineguys Psagot 2014 Merlot Merlot Psagot

63 rows × 13 columns

countryWines = wines.country

countryWines

0            Italy
1         Portugal
2               US
            ...   
129968      France
129969      France
129970      France
Name: country, Length: 129971, dtype: object
countryWines[pd.isnull]

913       NaN
3131      NaN
4243      NaN
         ... 
129408    NaN
129590    NaN
129900    NaN
Name: country, Length: 63, dtype: object
countryWines.isnull()

0         False
1         False
2         False
          ...  
129968    False
129969    False
129970    False
Name: country, Length: 129971, dtype: bool
countryWines = countryWines.fillna("Unknown")

countryWines[pd.isnull]

Series([], Name: country, dtype: object)
countryWines[913]

'Unknown'
countryWines = countryWines.replace("Unknown", "Invalid")

countryWines[913]

'Invalid'

Renaming 

myDataFrame.rename(columns={"oldColumnName": "newColumnName"})

myDataFrame.rename(index={oldValueIndex: newValueIndex})

myDataFrame.rename_axis("nameOfIndex", axis='rows').rename_axis("nameOfFields", axis='columns')
winesTest = wines
winesTest.head()
country description designation points price province region_1 region_2 taster_name taster_twitter_handle title variety winery
0 Italy Aromas include tropical fruit, broom, brimston... Vulkà Bianco 87 NaN Sicily & Sardinia Etna NaN Kerin O’Keefe @kerinokeefe Nicosia 2013 Vulkà Bianco (Etna) White Blend Nicosia
1 Portugal This is ripe and fruity, a wine that is smooth... Avidagos 87 15.0 Douro NaN NaN Roger Voss @vossroger Quinta dos Avidagos 2011 Avidagos Red (Douro) Portuguese Red Quinta dos Avidagos
2 US Tart and snappy, the flavors of lime flesh and... NaN 87 14.0 Oregon Willamette Valley Willamette Valley Paul Gregutt @paulgwine Rainstorm 2013 Pinot Gris (Willamette Valley) Pinot Gris Rainstorm
3 US Pineapple rind, lemon pith and orange blossom ... Reserve Late Harvest 87 13.0 Michigan Lake Michigan Shore NaN Alexander Peartree NaN St. Julian 2013 Reserve Late Harvest Riesling ... Riesling St. Julian
4 US Much like the regular bottling from 2012, this... Vintner's Reserve Wild Child Block 87 65.0 Oregon Willamette Valley Willamette Valley Paul Gregutt @paulgwine Sweet Cheeks 2012 Vintner's Reserve Wild Child... Pinot Noir Sweet Cheeks 
winesTest = winesTest.rename(columns={"points": "score"}).head()

winesTest.head()
country description designation score price province region_1 region_2 taster_name taster_twitter_handle title variety winery
0 Italy Aromas include tropical fruit, broom, brimston... Vulkà Bianco 87 NaN Sicily & Sardinia Etna NaN Kerin O’Keefe @kerinokeefe Nicosia 2013 Vulkà Bianco (Etna) White Blend Nicosia
1 Portugal This is ripe and fruity, a wine that is smooth... Avidagos 87 15.0 Douro NaN NaN Roger Voss @vossroger Quinta dos Avidagos 2011 Avidagos Red (Douro) Portuguese Red Quinta dos Avidagos
2 US Tart and snappy, the flavors of lime flesh and... NaN 87 14.0 Oregon Willamette Valley Willamette Valley Paul Gregutt @paulgwine Rainstorm 2013 Pinot Gris (Willamette Valley) Pinot Gris Rainstorm
3 US Pineapple rind, lemon pith and orange blossom ... Reserve Late Harvest 87 13.0 Michigan Lake Michigan Shore NaN Alexander Peartree NaN St. Julian 2013 Reserve Late Harvest Riesling ... Riesling St. Julian
4 US Much like the regular bottling from 2012, this... Vintner's Reserve Wild Child Block 87 65.0 Oregon Willamette Valley Willamette Valley Paul Gregutt @paulgwine Sweet Cheeks 2012 Vintner's Reserve Wild Child... Pinot Noir Sweet Cheeks 
winesTest.rename_axis("wineIndex", axis="rows")
country description designation score price province region_1 region_2 taster_name taster_twitter_handle title variety winery
wineIndex
0 Italy Aromas include tropical fruit, broom, brimston... Vulkà Bianco 87 NaN Sicily & Sardinia Etna NaN Kerin O’Keefe @kerinokeefe Nicosia 2013 Vulkà Bianco (Etna) White Blend Nicosia
1 Portugal This is ripe and fruity, a wine that is smooth... Avidagos 87 15.0 Douro NaN NaN Roger Voss @vossroger Quinta dos Avidagos 2011 Avidagos Red (Douro) Portuguese Red Quinta dos Avidagos
2 US Tart and snappy, the flavors of lime flesh and... NaN 87 14.0 Oregon Willamette Valley Willamette Valley Paul Gregutt @paulgwine Rainstorm 2013 Pinot Gris (Willamette Valley) Pinot Gris Rainstorm
3 US Pineapple rind, lemon pith and orange blossom ... Reserve Late Harvest 87 13.0 Michigan Lake Michigan Shore NaN Alexander Peartree NaN St. Julian 2013 Reserve Late Harvest Riesling ... Riesling St. Julian
4 US Much like the regular bottling from 2012, this... Vintner's Reserve Wild Child Block 87 65.0 Oregon Willamette Valley Willamette Valley Paul Gregutt @paulgwine Sweet Cheeks 2012 Vintner's Reserve Wild Child... Pinot Noir Sweet Cheeks 
winesTest.rename_axis("wineIndex", axis="rows").rename_axis("fields", axis="columns")
fields country description designation score price province region_1 region_2 taster_name taster_twitter_handle title variety winery
wineIndex
0 Italy Aromas include tropical fruit, broom, brimston... Vulkà Bianco 87 NaN Sicily & Sardinia Etna NaN Kerin O’Keefe @kerinokeefe Nicosia 2013 Vulkà Bianco (Etna) White Blend Nicosia
1 Portugal This is ripe and fruity, a wine that is smooth... Avidagos 87 15.0 Douro NaN NaN Roger Voss @vossroger Quinta dos Avidagos 2011 Avidagos Red (Douro) Portuguese Red Quinta dos Avidagos
2 US Tart and snappy, the flavors of lime flesh and... NaN 87 14.0 Oregon Willamette Valley Willamette Valley Paul Gregutt @paulgwine Rainstorm 2013 Pinot Gris (Willamette Valley) Pinot Gris Rainstorm
3 US Pineapple rind, lemon pith and orange blossom ... Reserve Late Harvest 87 13.0 Michigan Lake Michigan Shore NaN Alexander Peartree NaN St. Julian 2013 Reserve Late Harvest Riesling ... Riesling St. Julian
4 US Much like the regular bottling from 2012, this... Vintner's Reserve Wild Child Block 87 65.0 Oregon Willamette Valley Willamette Valley Paul Gregutt @paulgwine Sweet Cheeks 2012 Vintner's Reserve Wild Child... Pinot Noir Sweet Cheeks

Combining

When two files have the same fields (columns)​:

pd.concat([myDataFrameOrSeries1, myDataFrameOrSeries2])

When two files have the same index but not the same fields (columns)​:

myDataFrameOrSeriesLeft.join(myDataFrameOrSeriesRight, lsuffix="nameLeft", rsuffix="nameRight")