Selecting a row of pandas series/dataframe by integer index
Get a row in a Pandas DataFrame using a property called iloc
. Here's how:
A Series is just as simple:
Aiming to select a row with df[2]
can cause headaches! Here's why.
The battle of iloc vs loc
What warfare is iloc
trained for?
The iloc
attribute is skilled in integer-based indexing, following Python's indexing conventions. It's like the list you've always dreamed of!
Why would df[2]
lead to a disaster?
Giving df[2]
a shot? Think again! Pandas interprets this as looking for a column labeled '2', not accessing the 3rd row.
The charming art of slicing
If you're slicing with the []
operator, such as df[2:3]
, you've suddenly shifted to integer location selection, but not the exact row index.
Who would win in a showdown, iloc
or loc
?
While iloc
serves integer-based indexing, loc
dishes out label-based indexing. This means df.loc[2]
seeks a row labeled '2', not the 2nd row.
The fallen warrior, ix
df.ix
is the fallen legend of mixed-integer-label-based indexing. It has retired to bed after causing more confusion than convenience.
Direct integer indexing with a sprinkle of pandas magic
Numpy arrays - Fast and Furious
Pandas plays nicely with NumPy. Convert your DataFrame to a NumPy array for direct integer indexing:
The enigmatic 'SettingWithCopyWarning'
Beware the SettingWithCopyWarning
. It's reality TV for dataframes! Make sure you understand the drama of views vs copies while dealing with pandas.
The Python-Pandas paradox
Pandas is based on dict of Series, making it inherently different from Python indexing conventions. Our beloved library marches to its own drum beat.
Practical play and tips
Conducting a health checkup
Check your DataFrame's structure with df.index
before integer indexing to avoid unexpected results. It's like getting your vitals checked before a marathon!
404 Row not found
Accessing a row out of the DataFrame's range with iloc
invites an IndexError
. Remember to fit within the bounds!
The intriguing multilevel indices
With multilevel indices in your DataFrame, iloc
still provides access to rows, but things get messy. To learn this dance, consult the holy documentation.
Performance pep talk
Large dataset? .iloc
is your speedster! It excels at rapid row access as it skips the ceremony of label lookups.
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