Quickly adjust U.S. dollars for inflation using the Consumer Price Index (CPI)
A Python library that quickly adjusts U.S. dollars for inflation using the Consumer Price Index (CPI).
The library can be installed from the Python Package Index with any of the standard Python installation tools.
$ pipenv install cpi
Working with Python
Adjusting for inflation is as simple as providing a dollar value followed by the year it is from to the
inflate method. By default it is adjusted to its value in the most recent year available using "CPI-U" index recommended as a default by the Bureau of Labor Statistics.
>>> import cpi >>> cpi.inflate(100, 1950) 1017.0954356846472
If you'd like to adjust to a different year, submit it as an integer to the optional
to keyword argument.
>>> cpi.inflate(100, 1950, to=1960) 122.82157676348547
You can also adjust month to month. You should submit the months as
>>> from datetime import date >>> cpi.inflate(100, date(1950, 1, 1), to=date(2018, 1, 1)) 1072.2936170212768
You can adjust values using any of the other series published by the BLS as part of its "All Urban Consumers (CU)" survey. They offer more precise measures for different regions and items.
Submit one of the 60 areas tracked by the agency to inflate dollars in that region. You can find a complete list in the documentation.
>>> cpi.inflate(100, 1950, area="Los Angeles-Long Beach-Anaheim, CA") 1081.054852320675
You can do the same to inflate the price of 400 specific items lumped into the basket of goods that make up the overall index. You can find a complete list in the documentation.
>>> cpi.inflate(100, 1980, items="Housing") 309.77681874229353
And you can do both together.
>>> cpi.inflate(100, 1980, items="Housing", area="Los Angeles-Long Beach-Anaheim, CA") 344.5364396654719
Each of the 7,800 variations on the CU survey has a unique identifier. If you know which one you want, you can submit it directly.
>>> cpi.inflate(100, 2000, series_id="CUUSS12ASETB01") 165.15176374077112
If you'd like to retrieve the CPI value itself for any year, use the
>>> cpi.get(1950) 24.1
You can also do that by month.
>>> cpi.get(date(1950, 1, 1)) 23.5
The same keyword arguments are available.
>>> cpi.get(1980, items="Housing", area="Los Angeles-Long Beach-Anaheim, CA") 83.7
If you'd like to retrieve a particular CPI series for inspection, use the
get method. No configuration returns the default series.
>>> cpi.series.get() <Series: CUUR0000SA0: All items in U.S. city average, all urban consumers, not seasonally adjusted>
Alter the configuration options to retrieve variations based on item, area and other metadata.
>>> cpi.series.get(items="Housing", area="Los Angeles-Long Beach-Anaheim, CA") <Series: CUURS49ASAH: Housing in Los Angeles-Long Beach-Anaheim, CA, all urban consumers, not seasonally adjusted>
If you know a series's identifier code, you can submit that directly to
>>> cpi.series.get_by_id('CUURS49ASAH') <Series: CUURS49ASAH: Housing in Los Angeles-Long Beach-Anaheim, CA, all urban consumers, not seasonally adjusted>
Once retrieved, the complete set of index values for a series is accessible via the
>>> series = cpi.series.get(items="Housing", area="Los Angeles-Long Beach-Anaheim, CA") >>> series.indexes [<Index: 1997-01-01 (January): 155.4>, <Index: 1997-02-01 (February): 155.6>, <Index: 1997-03-01 (March): 155.5>, <Index: 1997-04-01 (April): 155.2>, <Index: 1997-05-01 (May): 156.1>, <Index: 1997-06-01 (June): 156.4>, <Index: 1997-07-01 (July): 156.9>, <Index: 1997-08-01 (August): 156.7>, <Index: 1997-09-01 (September): 157.1>, <Index: 1997-10-01 (October): 157.9>, ...
Working with the command line
The Python package also installs a command-line interface for
inflate that is available on the terminal.
It works the same as the Python library. First give it a value. Then a source year. By default it is adjusted to its value in the most recent year available.
$ inflate 100 1950 1017.09543568
If you'd like to adjust to a different year, submit it as an integer to the
$ inflate 100 1950 --to=1960 122.821576763
You can also adjust month to month. You should submit the months as parseable date strings.
$ inflate 100 1950-01-01 --to=2018-01-01 1054.75319149
Here are all its options.
$ inflate --help Usage: inflate [OPTIONS] VALUE YEAR_OR_MONTH Returns a dollar value adjusted for inflation. Options: --to TEXT The year or month to adjust the value to. --series_id TEXT The CPI data series used for the conversion. The default is the CPI-U. --help Show this message and exit.
Working with pandas
An inflation-adjusted column can quickly be added to a pandas DataFrame using the
apply method. Here is an example using data tracking the median household income in the United States from The Federal Reserve Bank of St. Louis.
>>> import cpi >>> import pandas as pd >>> df = pd.read("test.csv") >>> df.head() YEAR MEDIAN_HOUSEHOLD_INCOME 0 1984 22415 1 1985 23618 2 1986 24897 3 1987 26061 4 1988 27225 >>> df['ADJUSTED'] = df.apply(lambda x: cpi.inflate(x.MEDIAN_HOUSEHOLD_INCOME, x.YEAR), axis=1) >>> df.head() YEAR MEDIAN_HOUSEHOLD_INCOME ADJUSTED 0 1984 22415 52881.278152 1 1985 23618 53803.384387 2 1986 24897 55682.049635 3 1987 26061 56233.030986 4 1988 27225 56410.752325
The lists of CPI series and each's index values can be converted to a DataFrame using the
Here's how to get the series list:
>>> series_df = cpi.series.to_dataframe() >>>> series_df.info() <class 'pandas.core.frame.DataFrame'> RangeIndex: 7795 entries, 0 to 7794 Data columns (total 13 columns): area_code 7795 non-null object area_id 7795 non-null object area_name 7795 non-null object id 7795 non-null object items_code 7795 non-null object items_id 7795 non-null object items_name 7795 non-null object periodicity_code 7795 non-null object periodicity_id 7795 non-null object periodicity_name 7795 non-null object seasonally_adjusted 7795 non-null bool survey 7795 non-null object title 7795 non-null object dtypes: bool(1), object(12) memory usage: 738.5+ KB
Here's how to get a series's index values:
>>> series_obj = cpi.series.get( >>> items="Housing", >>> area="Los Angeles-Long Beach-Anaheim, CA" >>> ) >>> index_df = series_obj.to_dataframe() >>> index_df.info() <class 'pandas.core.frame.DataFrame'> RangeIndex: 553 entries, 0 to 552 Data columns (total 22 columns): date 553 non-null object period_abbreviation 553 non-null object period_code 553 non-null object period_id 553 non-null object period_month 553 non-null int64 period_name 553 non-null object period_type 553 non-null object series_area_code 553 non-null object series_area_id 553 non-null object series_area_name 553 non-null object series_id 553 non-null object series_items_code 553 non-null object series_items_id 553 non-null object series_items_name 553 non-null object series_periodicity_code 553 non-null object series_periodicity_id 553 non-null object series_periodicity_name 553 non-null object series_seasonally_adjusted 553 non-null bool series_survey 553 non-null object series_title 553 non-null object value 553 non-null float64 year 553 non-null int64 dtypes: bool(1), float64(1), int64(2), object(18) memory usage: 91.3+ KB
The adjustment is made using data provided by The Bureau of Labor Statistics at the U.S. Department of Labor.
Currently the library only supports inflation adjustments using series from the "All Urban Consumers (CU)" survey. The so-called "CPI-U" survey is the default, which is an average of all prices paid by all urban consumers. It is available from 1913 to the present. It is not seasonally adjusted. The dataset is identified by the BLS as "CUUR0000SA0." It is used as the default for most basic inflation calculations. All other series measuring all urban consumers are available by taking advantage of the library's options. The alternative survey of "Urban Wage Earners and Clerical Workers" is not yet available.
Updating the CPI
Since the BLS routinely releases new CPI new values, this library must periodically download the latest data. This library does not do this automatically. You must update the BLS dataset stored alongside the code yourself by running the following method:
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