concat() Method | Teradata Python Package - concat() Method - Teradata Package for Python

Use the concat() method to concatenate two teradataml DataFrame objects along the index axis. The operation is performed by carrying out a database-style union or union all operation.

Examples Prerequisite

Assume the table "admissions_train" exists and a DataFrame "df" is created based on this table using the command:

>>> df = DataFrame("admissions_train")

>>> df
   masters   gpa     stats programming admitted
id
22     yes  3.46    Novice    Beginner        0
36      no  3.00  Advanced      Novice        0
15     yes  4.00  Advanced    Advanced        1
38     yes  2.65  Advanced    Beginner        1
5       no  3.44    Novice      Novice        0
17      no  3.83  Advanced    Advanced        1
34     yes  3.85  Advanced    Beginner        0
13      no  4.00  Advanced      Novice        1
26     yes  3.57  Advanced    Advanced        1
19     yes  1.98  Advanced    Advanced        0

>>> df1 = df[df.gpa == 4].select(['id', 'stats', 'masters', 'gpa'])
>>> df1
       stats masters  gpa
id
13  Advanced      no  4.0
29    Novice     yes  4.0
15  Advanced     yes  4.0

>>> df2 = df[df.gpa < 2].select(['id', 'stats', 'programming', 'admitted'])
>>> df2
       stats programming admitted
id
24  Advanced      Novice        1
19  Advanced    Advanced        0

Example 1: Default behavior with default values for the optional arguments.

>>> # Default options
>>> cdf = df1.concat(df2)
>>> cdf
       stats masters  gpa programming admitted
id
19  Advanced    None  NaN    Advanced        0
24  Advanced    None  NaN      Novice        1
13  Advanced      no  4.0        None     None
29    Novice     yes  4.0        None     None
15  Advanced     yes  4.0        None     None

Example 2: concat() operation with 'join = inner'.

>>> cdf = df1.concat(df2, join='inner')
>>> cdf
       stats
id
19  Advanced
24  Advanced
13  Advanced
29    Novice
15  Advanced

Example 3: concat() operation with 'allow_duplicates=False'.

>>> # allow_duplicates = True (default)
>>> cdf = df1.concat(df2)
>>> cdf
       stats masters  gpa programming admitted
id
19  Advanced    None  NaN    Advanced        0
24  Advanced    None  NaN      Novice        1
13  Advanced      no  4.0        None     None
29    Novice     yes  4.0        None     None
15  Advanced     yes  4.0        None     None

>>> cdf = cdf.concat(df2)
>>> cdf
       stats masters  gpa programming admitted
id
19  Advanced    None  NaN    Advanced        0
13  Advanced      no  4.0        None     None
24  Advanced    None  NaN      Novice        1
24  Advanced    None  NaN      Novice        1
19  Advanced    None  NaN    Advanced        0
29    Novice     yes  4.0        None     None
15  Advanced     yes  4.0        None     None

>>> # allow_duplicates = False
>>> cdf = cdf.concat(df2, allow_duplicates=False)
>>> cdf
       stats masters  gpa programming admitted
id
19  Advanced    None  NaN    Advanced        0
29    Novice     yes  4.0        None     None
24  Advanced    None  NaN      Novice        1
15  Advanced     yes  4.0        None     None
13  Advanced      no  4.0        None     None

Example 4: concat() operation with 'sort=True'.

>>> cdf = df1.concat(df2, sort=True)
>>> cdf
   admitted  gpa masters programming     stats
id
19        0  NaN    None    Advanced  Advanced
24        1  NaN    None      Novice  Advanced
13     None  4.0      no        None  Advanced
29     None  4.0     yes        None    Novice
15     None  4.0     yes        None  Advanced