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# Sorting Lists for Lorenz Curve – Python

EDIT: This does not really work. Needs lots and lots of fixes. Use R instead.

This function will take a list of 100+ numbers, divide them into percentiles, and return a list that can be used to plot a Lorenz Curve.

## The Function

```from decimal import Decimal
from numpy import cumsum

def listPercentiles(list_items):

# check to see if there are at least 100 items
if len(list_items) < 100:
print '-- List is not long enough! --'

else:
# people in each percentile
int_per_cent = len(list_items)/100

# total entries
int_total_entries = sum(list_items)

# sort list from lowest to highes
list_items.sort()

# list of raw posts per percentile
list_pc_ents = []
for int_pcnt in range(0,len(list_items),int_per_cent):
# slice the list of entries to percentiles
list_each_percentile = list_items[int_pcnt:int_pcnt+int_per_cent]
# sum up all the entries in that percentile
int_raw_percentile = sum(list_each_percentile)
# change it to a percent of total entries
dec_percentile_entry = Decimal(int_raw_percentile)/Decimal(int_total_entries)
list_pc_ents.append(dec_percentile_entry)

# now do the cumsum
list_cumsum = list(cumsum(list_pc_ents))

list_int_formated = []
for dec_each_item in list_cumsum:
list_int_formated.append(float(dec_each_item))

return sum(list_pc_ents)
```

## Running the Function

First, we make a list full of integers. This time we will fill a list of 100 items with 1s.

```
# list of 100 items
list_100_items = []
for int_range in range(0,100):
list_100_items.append(1)

```

Now we run the above function

```list_percentiles = listPercentiles(list_100_items)

print list_percentiles
```

and that should return

```[0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1,
0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2,
0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3,
0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.4,
0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.5,
0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.6,
0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.7,
0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.8,
0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.9,
0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1.0]
```

PERFECT!!

EDIT: Not really perfect. Only works if the length of the list is a multiple of 100. Big flaw really.

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