python Programming Glossary: dataframe

http://stackoverflow.com/questions/10715965/add-one-row-in-a-pandas-dataframe

one row in a pandas.DataFrame I understand that pandas is designed to load fully populated.. understand that pandas is designed to load fully populated DataFrame but I need to create an empty DataFrame then add rows one by.. fully populated DataFrame but I need to create an empty DataFrame then add rows one by one . What is the best way to do this I..

NumPy or Pandas: Keeping array type as integer while having a NaN value

http://stackoverflow.com/questions/11548005/numpy-or-pandas-keeping-array-type-as-integer-while-having-a-nan-value

I am converting an in house data structure to a Pandas DataFrame. In our structure we have integer type columns that still have.. It seems to recast everything as a float if we make this a DataFrame but we'd really like to be int . Thoughts Things tried I tried.. tried I tried using the from_records function under pandas.DataFrame with coerce_float False and this did not help. I also tried..

Large, persistent DataFrame in pandas

http://stackoverflow.com/questions/11622652/large-persistent-dataframe-in-pandas

persistent DataFrame in pandas I am exploring switching to python and pandas as..

How to keep index when using pandas merge

http://stackoverflow.com/questions/11976503/how-to-keep-index-when-using-pandas-merge

merged dataset. However when I do the merge the resulting DataFrame has integer index. How can I specify that I want to keep the.. I want to keep the index from the left data frame In 441 a DataFrame data col1 1 2 3 'to_merge_on' 1 3 4 index a b c In 442 b DataFrame.. data col1 1 2 3 'to_merge_on' 1 3 4 index a b c In 442 b DataFrame data col2 1 2 3 'to_merge_on' 1 3 5 In 443 a Out 443 col1 to_merge_on..

Modifying a subset of rows in a pandas dataframe

http://stackoverflow.com/questions/12307099/modifying-a-subset-of-rows-in-a-pandas-dataframe

of rows in a pandas dataframe Assume I have a pandas DataFrame with two columns A and B. I'd like to modify this DataFrame.. with two columns A and B. I'd like to modify this DataFrame or create a copy so that B is always NaN whenever A is 0. How..

Benefits of panda's multiindex?

http://stackoverflow.com/questions/13226029/benefits-of-pandas-multiindex

of panda's multiindex So I learned that I can use DataFrame.groupby without having a MultiIndex to do subsampling cross.. sections. On the other hand when I have a MultiIndex on a DataFrame I still need to use DataFrame.groupby to do sub sampling cross.. I have a MultiIndex on a DataFrame I still need to use DataFrame.groupby to do sub sampling cross sections. So what is a MultiIndex..

HDF5 and SQLite. Concurrency, compression & I/O performance [closed]

http://stackoverflow.com/questions/16628329/hdf5-and-sqlite-concurrency-compression-i-o-performance

loop And here's the code import sqlite import os In 3 df DataFrame randn 1000000 2 columns list 'AB' class 'pandas.core.frame.DataFrame'.. randn 1000000 2 columns list 'AB' class 'pandas.core.frame.DataFrame' Int64Index 1000000 entries 0 to 999999 Data columns total 2..

Extracting XML into data frame with parent attribute as column title

http://stackoverflow.com/questions/16991691/extracting-xml-into-data-frame-with-parent-attribute-as-column-title

subfield in subfields dgrandchild.append subfield.text df DataFrame 'Parent' dparent 'Time' dTime 'grandchild' dgrandchld I could.. .attrib 'name' child.text data.append elem_data ndata DataFrame data python pandas lxml share improve this question I recommend.. improve this question I recommend just parsing to a DataFrame first similar to how you are already see below for my implementation..

Why are pandas merges in python faster than data.table merges in R?

http://stackoverflow.com/questions/8991709/why-are-pandas-merges-in-python-faster-than-data-table-merges-in-r

selection and merges. In this case database joins pandas' DataFrame contains no pre computed information that is being used for.. I should also add that the internal design of pandas' DataFrame is much more amenable to these kinds of operations than R's..

Parse dates when YYYYMMDD and HH are in separate columns using pandas in Python

http://stackoverflow.com/questions/11615504/parse-dates-when-yyyymmdd-and-hh-are-in-separate-columns-using-pandas-in-python

like to read it using pandas read_csv and have it in a dataframe indexed by the datetime. So far I've tried to implement the..

how to filter the dataframe rows of pandas by “within”/“in”?

http://stackoverflow.com/questions/12065885/how-to-filter-the-dataframe-rows-of-pandas-by-within-in

to filter the dataframe rows of pandas by &ldquo within&rdquo &ldquo in&rdquo i have.. of pandas by &ldquo within&rdquo &ldquo in&rdquo i have a dataframe 'rpt' of python pandas rpt class 'pandas.core.frame.DataFrame'..

Modifying a subset of rows in a pandas dataframe

http://stackoverflow.com/questions/12307099/modifying-a-subset-of-rows-in-a-pandas-dataframe

a subset of rows in a pandas dataframe Assume I have a pandas DataFrame with two columns A and B...

Pandas: create two new columns in a dataframe with values calculated from a pre-existing column

http://stackoverflow.com/questions/12356501/pandas-create-two-new-columns-in-a-dataframe-with-values-calculated-from-a-pre

create two new columns in a dataframe with values calculated from a pre existing column I am working.. the pandas library and I want to add two new columns to a dataframe df with n columns n 0 . These new columns result from the application.. the application of a function to one of the columns in the dataframe. The function to apply is like def calculate x ...operate.....

Benefits of panda's multiindex?

http://stackoverflow.com/questions/13226029/benefits-of-pandas-multiindex

structure DataFrame for example. Imagine constructing a dataframe using MultiIndex like this import pandas as pd import numpy.. zip np.arrays columns 'A' 'B' df # This is the dataframe we have generated A B one 1 0.732470 0.313871 2 0.031109 2.068794.. even grab a cross section either rows or columns from our dataframe... By rows In 47 df.xs 'one' Out 47 A B 1 0.732470 0.313871..

How to trouble-shoot HDFStore Exception: cannot find the correct atom type

http://stackoverflow.com/questions/15488809/how-to-trouble-shoot-hdfstore-exception-cannot-find-the-correct-atom-type

dtypes float64 2 int64 6 object 45 Code to store the dataframe In 30 store pd.HDFStore 'test0.h5' 'w' In 31 for chunk in pd.read_csv.. 'df' chunk index False Note that if I use store.put on a dataframe imported in one shot I can store it successfully albeit slowly.. out of range UPDATE 1 Jeff's tip about lists stored in the dataframe led me to investigate embedded commas. pandas.read_csv is correctly..

How to insert pandas dataframe via mysqldb into database?

http://stackoverflow.com/questions/16476413/how-to-insert-pandas-dataframe-via-mysqldb-into-database

to insert pandas dataframe via mysqldb into database I can connect to my local mysql database.. is can I directly instruct mysqldb to take an entire dataframe and insert it into an existing table or do I need to iterate.. simple table with ID and two data columns and a matching dataframe python mysql pandas mysql python share improve this question..

Pandas: reshaping data

http://stackoverflow.com/questions/16637171/pandas-reshaping-data

Beauty Spas And I want to radically reshape it into a dataframe that looks something like this... Yellow Automotive Pizza 14..

Parsing xml to pandas data frame throws memory error

http://stackoverflow.com/questions/16922432/parsing-xml-to-pandas-data-frame-throws-memory-error

be put into lists separately before being pushed into the dataframe. The memory error was being caused by the multiple elements..

selecting across multiple columns with python pandas?

http://stackoverflow.com/questions/8916302/selecting-across-multiple-columns-with-python-pandas

across multiple columns with python pandas I have a dataframe df in pandas that was built using pandas.read_table from a csv.. was built using pandas.read_table from a csv file. The dataframe has several columns and it is indexed by one of the columns.. that column used for indexing. How can I select rows of my dataframe based on a complex filter applied to multiple columns I can..

Understanding pandas dataframe indexing

http://stackoverflow.com/questions/14192741/understanding-pandas-dataframe-indexing

'D' you first do boolean slicing leading to a copy of the Dataframe then you choose a column 'D' . In df.D df.key 1 3.4 you first..

Pandas Pivot tables row subtotals

http://stackoverflow.com/questions/15570099/pandas-pivot-tables-row-subtotals

row subtotals I'm using Pandas 0.10.1 Considering this Dataframe Date State City SalesToday SalesMTD SalesYTD 20130320 stA ctA..

PyQt - Column of Checkboxes in a QTableView

http://stackoverflow.com/questions/17748546/pyqt-column-of-checkboxes-in-a-qtableview

the data method Here it is I had to create a class called Dataframe to simulate the panda Dataframe structure. Please replace all.. to create a class called Dataframe to simulate the panda Dataframe structure. Please replace all the if has_panda statements by.. class Dataframe dict def __init__ self columns values if len values len columns..