Combining

Combine multiple DataFrames through concatenation and merging.

We'll cover the following...

Chapter Goals:

  • Understand the methods used to combine DataFrame objects
  • Write code for combining DataFrames

In the previous chapter, we discussed the append function for concatenating DataFrame rows. To concatenate multiple DataFrames along either rows or columns, we use the pd.concat function.

The code below shows example usages of pd.concat.

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df1 = pd.DataFrame({'c1':[1,2], 'c2':[3,4]},
index=['r1','r2'])
df2 = pd.DataFrame({'c1':[5,6], 'c2':[7,8]},
index=['r1','r2'])
df3 = pd.DataFrame({'c1':[5,6], 'c2':[7,8]})
concat = pd.concat([df1, df2], axis=1)
# Newline to separate print statements
print('{}\n'.format(concat))
concat = pd.concat([df2, df1, df3])
print('{}\n'.format(concat))
concat = pd.concat([df1, df3], axis=1)
print('{}\n'.format(concat))

The pd.concat function ...