Ho do I create a new column and values to it [duplicate] - python

This question already has answers here:
Pandas Merging 101
(8 answers)
Closed 1 year ago.
I have two csv files with data. They both have a common column (county). The first file just has the counties while the second file has counties together with their population. I have a script which I thought would be able to create a new column of population in the first file. Note that the order of the counties in both files is totally different.
File one:
Id
County
1
Nairobi
2
Mombasa
3
Kisumu
4
Nakuru
File two:
Id
County
Population
1
Kisumu
1,250,200
2
Nairobi
4,560,700
3
Nakuru
2,673,800
4
Mombasa
3,167,900
I wanted to create a new column in the first table as Population and parse through the second table and pick population of each county, like in the table below.
Id
County
Population
1
Nairobi
4,560,700
2
Mombasa
3,167,900
3
Kisumu
1,250,200
4
Nakuru
2,673,800
Below is my code, I got a bit confused on how to execute that. Please help.
data = pd.read_csv('counties.csv');
county_names = data['COUNTY']
ref_data = pd.read_csv('kenya-population-by-sex-and-county.csv', skiprows=8, header=None)
ref_data.columns = ['County', 'Male', 'Female', 'Intersex', 'Total']
list_count = []
for item in county_names.tolist():
compare = ref_data['County'].tolist()
pop = ref_data['Total']
if item in compare:
list_count.append(item)
pop
else:
print(item + " is not in list")```

You can simply create a pandas dataframe containing County and Population and merge it with the first dataframe where only County was there. Also there are many joining options available to fulfill your different needs.

Related

How to split two first names that together in two different words in python

I am trying to split misspelled first names. Most of them are joined together. I was wondering if there is any way to separate two first names that are together into two different words.
For example, if the misspelled name is trujillohernandez then to be separated to trujillo hernandez.
I am trying to create a function that can do this for a whole column with thousands of misspelled names like the example above. However, I haven't been successful. Spell-checkers libraries do not work given that these are first names and they are Hispanic names.
I would be really grateful if you can help to develop some sort of function to make it happen.
As noted in the comments above not having a list of possible names will cause a problem. However, and perhaps not perfect, but to offer something try...
Given a dataframe example like...
Name
0 sofíagomez
1 isabelladelgado
2 luisvazquez
3 juanhernandez
4 valentinatrujillo
5 camilagutierrez
6 joséramos
7 carlossantana
Code (Python):
import pandas as pd
import requests
# longest list of hispanic surnames I could find in a table
url = r'https://namecensus.com/data/hispanic.html'
# download the table into a frame and clean up the header
page = requests.get(url)
table = pd.read_html(page.text.replace('<br />',' '))
df = table[0]
df.columns = df.iloc[0]
df = df[1:]
# move the frame of surnames to a list
last_names = df['Last name / Surname'].tolist()
last_names = [each_string.lower() for each_string in last_names]
# create a test dataframe of joined firstnames and lastnames
data = {'Name' : ['sofíagomez', 'isabelladelgado', 'luisvazquez', 'juanhernandez', 'valentinatrujillo', 'camilagutierrez', 'joséramos', 'carlossantana']}
df = pd.DataFrame(data, columns=['Name'])
# create new columns for the matched names
lastname = '({})'.format('|'.join(last_names))
df['Firstname'] = df.Name.str.replace(str(lastname)+'$', '', regex=True).fillna('--not found--')
df['Lastname'] = df.Name.str.extract(str(lastname)+'$', expand=False).fillna('--not found--')
# output the dataframe
print('\n\n')
print(df)
Outputs:
Name Firstname Lastname
0 sofíagomez sofía gomez
1 isabelladelgado isabella delgado
2 luisvazquez luis vazquez
3 juanhernandez juan hernandez
4 valentinatrujillo valentina trujillo
5 camilagutierrez camila gutierrez
6 joséramos josé ramos
7 carlossantana carlos santana
Further cleanup may be required but perhaps it gets the majority of names split.

Check if a string is present in multiple lists

I am trying to categorize a dataset based on the string that contains the name of the different objects of the dataset.
The dataset is composed of 3 columns, df['Name'], df['Category'] and df['Sub_Category'], the Category and Sub_Category columns are empty.
For each row I would like to check in different lists of words if the name of the object contains at least one word in one of the list. Based on this first check I would like to attribute a value to the category column. If it finds more than 1 word in 2 different lists I would like to attribute 2 values to the object in the category column.
Moreover, I would like to be able to identify which word has been checked in which list in order to attribute a value to the sub_category column.
Until now, I have been able to do it with only one list, but I am not able to identity which word has been checked and the code is very long to run.
Here is my code (where I added an example of names found in my dataset as df['Name']) :
import pandas as pd
import numpy as np
df['Name'] = ['vitrine murale vintage','commode ancienne', 'lustre antique', 'solex', 'sculpture médievale', 'jante voiture', 'lit et matelas', 'turbine moteur']
furniture_check = ['canape', 'chaise', 'buffet','table','commode','lit']
vehicle_check = ['solex','voiture','moto','scooter']
art_check = ['tableau','scuplture', 'tapisserie']
for idx, row in df.iterrows():
for c in furniture_check:
if c in row['Name']:
df.loc[idx, 'Category'] = 'Meubles'
Any help would be appreciated
Here is an approach that expands lists, merges them and re-combines them.
df = pd.DataFrame({"name":['vitrine murale vintage','commode ancienne', 'lustre antique', 'solex', 'sculpture médievale', 'jante voiture', 'lit et matelas', 'turbine moteur']})
furniture_check = ['canape', 'chaise', 'buffet','table','commode','lit']
vehicle_check = ['solex','voiture','moto','scooter']
art_check = ['tableau','scuplture', 'tapisserie']
# put categories into a dataframe
dfcat = pd.DataFrame([{"category":"furniture","values":furniture_check},
{"category":"vechile","values":vehicle_check},
{"category":"art","values":art_check}])
# turn apace delimited "name" column into a list
dfcatlist = (df.assign(name=df["name"].apply(lambda x: x.split(" ")))
# explode list so it can be used as join. reset_index() to keep a copy of index of original DF
.explode("name").reset_index()
# merge exploded names on both side
.merge(dfcat.explode("values"), left_on="name", right_on="values")
# where there are multiple categoryies, make it a list
.groupby("index", as_index=False).agg({"category":lambda s: list(s)})
# but original index back...
.set_index("index")
)
# simple join and have names and list of associated categories
df.join(dfcatlist)
name
category
0
vitrine murale vintage
nan
1
commode ancienne
['furniture']
2
lustre antique
nan
3
solex
['vechile']
4
sculpture médievale
nan
5
jante voiture
['vechile']
6
lit et matelas
['furniture']
7
turbine moteur
nan

Import CSV file where last column has many separators [duplicate]

This question already has an answer here:
python pandas read_csv delimiter in column data
(1 answer)
Closed 2 years ago.
The dataset looks like this:
region,state,latitude,longitude,status
florida,FL,27.8333,-81.717,open,for,activity
georgia,GA,32.9866,-83.6487,open
hawaii,HI,21.1098,-157.5311,illegal,stuff
iowa,IA,42.0046,-93.214,medical,limited
As you can see, the last column sometimes has separators in it. This makes it hard to import the CSV file in pandas using read_csv(). The only way I can import the file is by adding the parameter error_bad_lines=False to the function. But this way I'm losing some of the data.
How can I import the CSV file without losing data?
I would read the file as one single column and parse manually:
df = pd.read_csv(filename, sep='\t')
pat = ','.join([f'(?P<{x}>[^\,]*)' for x in ['region','state','latitude','longitute']])
pat = '^'+ pat + ',(?P<status>.*)$'
df = df.iloc[:,0].str.extract(pat)
Output:
region state latitude longitute status
0 florida FL 27.8333 -81.717 open,for,activity
1 georgia GA 32.9866 -83.6487 open
2 hawaii HI 21.1098 -157.5311 illegal,stuff
3 iowa IA 42.0046 -93.214 medical,limited
Have you tried the old-school technique with the split function? A major downside is that you'd end up losing data or bumping into errors if your data has a , in any of the first 4 fields/columns, but if not, you could use it.
data = open(file,'r').read().split('\n')
for line in data:
items = line.split(',',4). # Assuming there are 4 standard columns, and the 5th column has commas
Each row items would look, for example, like this:
['hawaii', 'HI', '21.1098', '-157.5311', 'illegal,stuff']

How to group data in a DataFrame and also show the number of row in that group?

first of all, I have no background in computer language and I am learning Python.
I'm trying to group some data in a data frame.
[dataframe "cafe_df_merged"]
Actually, I want to create a new data frame shows the 'city_number', 'city' (which is a name), and also the number of cafes in the same city. So, it should have 3 columns; 'city_number', 'city' and 'number_of_cafe'
However, I have tried to use the group by but the result did not come out as I expected.
city_directory = cafe_df_merged[['city_number', 'city']]
city_directory = city_directory.groupby('city').count()
city_directory
[the result]
How should I do this? Please help, thanks.
There are likely other ways of doing this as well, but something like this should work:
import pandas as pd
import numpy as np
# Create a reproducible example
places = [[['starbucks', 'new_york', '1234']]*5, [['bean_dream', 'boston', '3456']]*4, \
[['coffee_today', 'jersey', '7643']]*3, [['coffee_today', 'DC', '8902']]*3, \
[['starbucks', 'nowwhere', '2674']]*2]
places = [p for sub in places for p in sub]
# a dataframe containing all information
city_directory = pd.DataFrame(places, columns=['shop','city', 'id'])
# make a new dataframe with just cities and ids
# drop duplicate rows
city_info = city_directory.loc[:, ['city','id']].drop_duplicates()
# get the cafe counts (number of cafes)
cafe_count = city_directory.groupby('city').count().iloc[:,0]
# add the cafe counts to the dataframe
city_info['cafe_count'] = cafe_count[city_info['city']].to_numpy()
# reset the index
city_info = city_info.reset_index(drop=True)
city_info now yields the following:
city id cafe_count
0 new_york 1234 5
1 boston 3456 4
2 jersey 7643 3
3 DC 8902 3
4 nowwhere 2674 2
And part of the example dataframe, city_directory.tail(), looks like this:
shop city id
12 coffee_today DC 8902
13 coffee_today DC 8902
14 coffee_today DC 8902
15 starbucks nowwhere 2674
16 starbucks nowwhere 2674
Opinion: As a side note, it might be easier to get comfortable with regular Python first before diving deep into the world of pandas and numpy. Otherwise, it might be a bit overwhelming.

Rearrange CSV data

I have 2 csv files with different sequence of columns. For e.g. the first file starts with 10 digits mobile numbers while that column is at number 4 in the second file.
I need to merge all the customer data into a single csv file. The order of the columns should be as follows:
mobile pincode model Name Address Location pincode date
mobile Name Address Model Location pincode Date
9845299999 Raj Shah nagar No 22 Rivi Building 7Th Main I Crz Mumbai 17/02/2011
9880877777 Managing Partner M/S Aitas # 1010, 124Th Main, Bk Stage. - Bmw 320 D Hyderabad 560070 30-Dec-11
Name Address Location mobile pincode Date Model
Asvi Developers pvt Ltd fantry Road Nariman Point, 1St Floor, No. 150 Chennai 9844066666 13/11/2011 Crz
L R Shiva Gaikwad & Sudha Gaikwad # 42, Suvarna Mansion, 1St Cross, 17Th Main, Banjara Hill, B S K Stage,- Bangalore 9844233333 560085 40859 Mercedes_E 350 Cdi
Second task and that may be slightly difficult is that the new files expected may have a totally different column sequence. In that case I need to extract 10 digits mobile number and 6 digits pincode column. I need to write the code that will guess the city column if it matches with any of the given city list. The new files are expected to have relevant column headings but the column heading may be slightly different. for e.g. "customer address" instead of "address". How do I handle such data?
sed 's/.*\([0-9]\{10\}\).*/\1,&/' input
I have been suggested to use sed to rearrange the 10 digits column at the beginning. But I do also need to rearrange the text columns. For e.g. if a column matches the entries in the following list then it is undoubtedly model column.
['Crz', 'Bmw 320 D', 'Benz', 'Mercedes_E 350 Cdi', 'Toyota_Corolla He 1.8']
If any column matches 10% of the entries with the above list then it is a "model" column and should be at number 3 followed by mobile and pincode.
For your first question, I suggest using pandas to load both files and then concat. After that you can rearrange your columns.
import pandas as pd
dataframe1 = pd.read_csv('file1.csv')
dataframe2 = pd.read_csv('file2.csv')
combined = pd.concat([dataframe1, dataframe2]) #the columns will be ordered alphabetically
To get desired order,
result_df = combined[['mobile', 'pincode', 'model', 'Name', 'Address', 'Location', 'pincode', 'date']]
and then result_df.to_csv('oupput.csv', index=False) to export to csv file.
For the second one, you can do something like this (assuming you have loaded a csv file into df like above)
match_model = lambda m: m in ['Crz', 'Bmw 320 D', 'Benz', 'Mercedes_E 350 Cdi', 'Toyota_Corolla He 1.8']
for c in df:
if df[c].map(match_model).sum()/len(df) > 0.1:
print "Column %s is 'Model'"% c
df.rename(columns={c:'Model'}, inplace=True)
You can modify the matching function match_model to use regex instead if you want.

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