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Series from dict

A dictionary becomes a Series where the keys are the index and the values are the data.

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  1. Series from dict
Syntax
python
s = pd.Series({"label1": value1, "label2": value2})

Series from dict

Passing a dict to pd.Series uses keys as index labels and values as data, in insertion order. Supply an index to select or reorder keys; missing keys become NaN. This is a natural way to model labelled data.

Note: Passing a list of keys as index picks only those keys.

Example: Series from dict

python
import pandas as pd

ages = {"Ann": 28, "Bob": 35, "Cy": 41}
s = pd.Series(ages)
print(s)
print(pd.Series(ages, index=["Cy", "Ann", "Zed"]))

# Output:
# Ann    28
# Bob    35
# Cy     41
# dtype: int64
# Cy     41.0
# Ann    28.0
# Zed     NaN
# dtype: float64
Related Topics
{# common_mistakes/chapter_summary/browser_support: on Hindi pages the view already swaps in the hi_ translation fields (or blanks these out if untranslated), so this renders correctly for both languages without a lang_code check here. #}
Common Mistakes
  1. Expecting dict order to be sorted
  2. Passing an index with keys not in the dict and forgetting NaN
  3. Unhashable dictionary values
Chapter Summary
  • Keys become the index
  • Values become the data
  • A custom index selects keys
  • Missing keys give NaN
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