Question 1: The file phone.txt stores the lines in the format code:number
import pandas as pd
import sqlite3
con = sqlite3.connect('database.db')
data = pd.read_csv('phone.txt', sep='\t', header=None)
data.to_sql('post_table', con, if_exists='replace', index=False)
I want to load all the data from the phone.txt file into the database.db database. But I have everything loaded in one column. And I need to load in two columns:
code
number
How to do it?
Question 2: after downloading the information to the database, how can I find the number by code? For example, if I want to find out what number code = 7 (answer: 9062621390).
Question 1
In your example pandas is not able to distinguish between the code and the number since your file is :-separated. When reading your file you need to change the separator to : and also specify columns since your csv doesn't seem to have a header like so
data = pd.read_csv('phone.txt',
sep=':',
names=['code', 'number'])
Question 2
After putting your data to the database you can query it as follows
number = pd.read_sql_query('SELECT number FROM post_table WHERE code = (?)',
con,
params=(code,))
where con is your sqlite connection.
Related
I am building an API to save CSVs from Sharepoint Rest API using python 3. I am using a public dataset as an example. The original csv has 3 columns Group,Team,FIFA Ranking with corresponding data in the rows.For reference. the original csv on sharepoint ui looks like this:
after using data=response.content the output of data is:
b'Group,Team,FIFA Ranking\r\nA,Qatar,50\r\nA,Ecuador,44\r\nA,Senegal,18\r\nA,Netherlands,8\r\nB,England,5\r\nB,Iran,20\r\nB,United States,16\r\nB,Wales,19\r\nC,Argentina,3\r\nC,Saudi Arabia,51\r\nC,Mexico,13\r\nC,Poland,26\r\nD,France,4\r\nD,Australia,38\r\nD,Denmark,10\r\nD,Tunisia,30\r\nE,Spain,7\r\nE,Costa Rica,31\r\nE,Germany,11\r\nE,Japan,24\r\nF,Belgium,2\r\nF,Canada,41\r\nF,Morocco,22\r\nF,Croatia,12\r\nG,Brazil,1\r\nG,Serbia,21\r\nG,Switzerland,15\r\nG,Cameroon,43\r\nH,Portugal,9\r\nH,Ghana,61\r\nH,Uruguay,14\r\nH,South Korea,28\r\n'
how do I convert the above to csv that pandas can manipulate with the columns being Group,Team,FIFA and then the corresponding data dynamically so this method works for any csv.
I tried:
data=response.content.decode('utf-8', 'ignore').split(',')
however, when I convert the data variable to a dataframe then export the csv the csv just returns all the values in one column.
I tried:
data=response.content.decode('utf-8') or data=response.content.decode('utf-8', 'ignore') without the split
however, pandas does not take this in as a valid df and returns invalid use of dataframe constructor
I tried:
data=json.loads(response.content)
however, the format itself is invalid json format as you will get the error json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)
Given:
data = b'Group,Team,FIFA Ranking\r\nA,Qatar,50\r\nA,Ecuador,44\r\nA,Senegal,18\r\n' #...
If you just want a CSV version of your data you can simply do:
with open("foo.csv", "wt", encoding="utf-8", newline="") as file_out:
file_out.writelines(data.decode())
If your objective is to load this data into a pandas dataframe and the CSV is not actually important, you can:
import io
import pandas
foo = pandas.read_csv(io.StringIO(data.decode()))
print(foo)
As per below data, using Python how can I get Headers column value for the corresponding given input from DB & Table column.
DB Table Headers
Oracle Cust Id,Name,Mail,Phone,City,County
Oracle Cli Cid,shopNo,State
Oracle Addr Street,Area,City,Country
SqlSer Usr Name,Id,Addr
SqlSer Log LogId,Env,Stg
MySql Loc Flat,Add,Pin,Country
MySql Data Id,Txt,TaskId,No
Output: Suppose if i pass, Oracle & Cli as parameters, then it should return the value as "Cid,shopNo,State" in a list.
Trying with python dictionary, but it takes 2 values key and value. But i have 3 values. how to get ?
Looks like your data is in some sort of tabular format. In that case I would recommend using the pandas package, which is very convenient if you are working with tabular data.
pandas can read data into a DataFrame from a CSV file using pandas.read_csv. This dataframe you can then filter using the column names and the required values.
In the example below I assume that your data is tab (\t) separated. I read in the data from a string using io.StringIO. Normally you would just use pandas.read_csv('filename.csv').
import pandas as pd
import io
data = """DB\tTable\tHeaders
Oracle\tCust\tId,Name,Mail,Phone,City,County
Oracle\tCli\tCid,shopNo,State
Oracle\tAddr\tStreet,Area,City,Country
SqlSer\tUsr\tName,Id,Addr
SqlSer\tLog\tLogId,Env,Stg
MySql\tLoc\tFlat,Add,Pin,Country
MySql\tData\tId,Txt,TaskId,No"""
dataframe = pd.read_csv(io.StringIO(data), sep='\t')
db_is_oracle = dataframe['DB'] == 'Oracle'
table_is_cli = dataframe['Table'] == 'Cli'
filtered_dataframe = dataframe[db_is_oracle & table_is_cli]
print(filtered_dataframe)
This will result in :
DB Table Headers
1 Oracle Cli Cid,shopNo,State
Or to get the actual headers of the first match:
print(filtered_dataframe['Headers'].iloc[0])
>>> Cid,shopNo,State
I need to analyse some spectral data in real-time and plot it as a self-updating graph.
The program I use outputs a text file every two seconds.
Usually I do the analysis after gathering the data and the code works just fine. I create a dataframe, where each csv file represents a column. The problem is, with several thousands of csv files, the import becomes very slow and creating a dataframe out of all the csv files takes usually more than half an hour.
Below the code for creating the dataframe from multiple csv files.
''' import, append and concat files into one dataframe '''
all_files = glob.glob(os.path.join(path, filter + "*.txt")) # path to the files by joining path and file name
all_files.sort(key=os.path.getmtime)
data_frame = []
name = []
for file in (all_files):
creation_time = os.path.getmtime(file)
readible_date = datetime.fromtimestamp(creation_time)
df = pd.read_csv(file, index_col=0, header=None, sep='\t', engine='python', decimal=",", skiprows = 15)
df.rename(columns={1: readible_date}, inplace=True)
data_frame.append(df)
full_spectra = pd.concat(data_frame, axis=1)
for column in full_spectra.columns:
time_step = column - full_spectra.columns[0]
minutes = time_step.total_seconds()/60
name.append(minutes)
full_spectra.columns = name
return full_spectra
The solution I thought of was using the watchdog module and everytime a new textfile is created it gets appended as a new column to the existing dataframe and the updated dataframe is plotted. Because then, I do not need to loop over all csv files all the time.
I found a very nice example on how to use watchdog here
My problem is, I could not find a solution how after detecting the new file with watchdog, to read it and append it to the existing dataframe.
A minimalistic example code should look something like this:
def latest_filename():
"""a function that checks within a directoy for new textfiles"""
return(filename)
df = pd.DataFrame() #create a dataframe
newdata = pd.read_csv(latest_filename) #The new file is found by watchdog
df["newcolumn"] = newdata["desiredcolumn"] #append the new data as column
df.plot() #plot the data
The plotting part should be easy and my thoughts were to adapt the code presented here. I am more concerned with the self-updating dataframe.
I appreciate any help or other solutions that would solve my issue!
I'm working on a mechanical engineering project. For the following code, the user enters the number of cylinders that their compressor has. A dataframe is then created with the correct number of columns and is exported to Excel as a CSV file.
The outputted dataframe looks exactly like I want it to as shown in the first link, but when opened in Excel it looks like the image in the second link:
1.my dataframe
2.Excel Table
Why is my dataframe not exporting properly to Excel and what can I do to get the same dataframe in Excel?
import pandas as pd
CylinderNo=int(input('Enter CylinderNo: '))
new_number=CylinderNo*3
list1=[]
for i in range(1,CylinderNo+1):
for j in range(0,3):
Cylinder_name=str('CylinderNo ')+str(i)
list1.append(Cylinder_name)
df = pd.DataFrame(list1,columns =['Kurbel/Zylinder'])
list2=['Triebwerk', 'Packung','Ventile']*CylinderNo
Bauteil = {'Bauteil': list2}
df2 = pd.DataFrame (Bauteil, columns = ['Bauteil'])
new=pd.concat([df, df2], axis=1)
list3=['Nan','Nan','Nan']*CylinderNo
Bewertung={'Bewertung': list3}
df3 = pd.DataFrame (Bewertung, columns = ['Bewertung'])
new2=pd.concat([new, df3], axis=1)
Empfehlung={'Empfehlung': list3}
df4 = pd.DataFrame (Empfehlung, columns = ['Empfehlung'])
new3=pd.concat([new2, df4], axis=1)
new3.set_index('Kurbel/Zylinder')
new3 = new3.set_index('Kurbel/Zylinder', append=True).swaplevel(0,1)
#export dataframe to csv
new3.to_csv('new3.csv')
To be clear, a comma-separated values (CSV) file is not an Excel format type or table. It is a delimited text file that Excel like other applications can open.
What you are comparing is simply presentation. Both data frames are exactly the same. For multindex data frames, Pandas print output does not repeat index values for readability on the console or IDE like Jupyter. But such values are not removed from underlying data frame only its presentation. If you re-order indexes, you will see this presentation changes. The full complete data frame is what is exported to CSV. And ideally for data integrity, you want the full data set exported with to_csv to be import-able back into Pandas with read_csv (which can set indexes) or other languages and applications.
Essentially, CSV is an industry format to store and transfer data. Consider using Excel spreadsheets, HTML markdown, or other reporting formats for your presentation needs. Therefore, to_csv may not be the best method. You can try to build text file manually with Python i/o write methods, with open('new.csv', 'w') as f, but will be an extensive workaround See also #Jeff's answer here but do note the latter part of solution does remove data.
I am trying to read a .sas7bdat file using pandas and I am having a hard time because pandas is converting strings values that look like a number into float.
For example, if I have a telephone number like '348386789' and I read it with the following code:
import pandas as pd
df = pd.read_sas('test.sas7bdat', format='sas7bdat', encoding='utf-8')
The output would be 348386789.0!
I can convert every single column with something like df['number'].astype(int).astype(str) but this would be very unefficent.
There is the same problem in the read_csv function but there you can use the argument dtype that sets the type for the required column (es. dtype={'number': str)}).
Is there a better way to read values in the desired format and use it in a dataframe?
UPDATE
I even tried sas7bdat.py and pyreadstat with the same results. You might say that the problem is in the data but using an online tool to read sas7bdat the data seems correct.
Code for the other two libraries:
# pyreadstat module
import pyreadstat
df2, meta = pyreadstat.read_sas7bdat('test.sas7bdat')
# sas7bdat module
from sas7bdat import SAS7BDAT
reader = SAS7BDAT('test.sas7bdat')
df_sas = reader.to_data_frame()
If you want to try, (and you have a SAS license), you can create a .sas7bdat file with the following content:
column_1,column_2,column_3
11,20190129,5434
19,20190228,5236
59,20190328,10448
76,20190129,5434
Use sas7bdat.py instead. That typically preserves the dataset formats better.
IF a particular column is defined as character in the SAS dataset, then sas7bdat will read it as as string regardless of how the contents look like. As a lazy example, I created this dataset in SAS:
data test;
id = '1111111'; val = 1; output;
id = '2222222'; val = 2; output;
run;
And then ran the following Python code on it:
reader = SAS7BDAT('test.sas7bdat')
df = reader.to_data_frame()
print(df)
cols = reader.columns
for col in cols:
print(str(col.name) + " " + str(col.type))
Here is what I see:
id val
0 1111111 1.0
1 2222222 2.0
b'id' string
b'val' number
If you are looking to 'intelligently' convert numbers to strings based on context, then you may need to look elsewhere. Any SAS dataset reader is just going to read based on the format specified within the dataset at best.