I would like to merge two DataFrames, and keep the index from the first frame as the index on the merged dataset. However, when I do the merge, the resulting DataFrame has integer index. How can I specify that I want to keep the index from the left data frame? In [4]: a = pd.DataFrame({‘col1’: … Read more
My dataframe has a DOB column (example format 1/1/2016) which by default gets converted to Pandas dtype ‘object’. Converting this to date format with df[‘DOB’] = pd.to_datetime(df[‘DOB’]), the date gets converted to: 2016-01-26 and its dtype is: datetime64[ns]. Now I want to convert this date format to 01/26/2016 or any other general date format. How … Read more
Let’s say df is a pandas DataFrame. I would like to find all columns of numeric type. Something like: isNumeric = is_numeric(df) 12 Answers 12
I have an existing plot that was created with pandas like this: df[‘myvar’].plot(kind=’bar’) The y axis is format as float and I want to change the y axis to percentages. All of the solutions I found use ax.xyz syntax and I can only place code below the line above that creates the plot (I cannot … Read more
I want to read a .xlsx file using the Pandas Library of python and port the data to a postgreSQL table. All I could do up until now is: import pandas as pd data = pd.ExcelFile(“*File Name*”) Now I know that the step got executed successfully, but I want to know how i can parse … Read more
I am sure there is an obvious way to do this but cant think of anything slick right now. Basically instead of raising exception I would like to get True or False to see if a value exists in pandas df index. import pandas as pd df = pd.DataFrame({‘test’:[1,2,3,4]}, index=[‘a’,’b’,’c’,’d’]) df.loc[‘g’] # (should give False) … Read more
I have the following data frames: print(df_a) mukey DI PI 0 100000 35 14 1 1000005 44 14 2 1000006 44 14 3 1000007 43 13 4 1000008 43 13 print(df_b) mukey niccdcd 0 190236 4 1 190237 6 2 190238 7 3 190239 4 4 190240 7 When I try to join these data … Read more
I am trying to access the index of a row in a function applied across an entire DataFrame in Pandas. I have something like this: df = pandas.DataFrame([[1,2,3],[4,5,6]], columns=[‘a’,’b’,’c’]) >>> df a b c 0 1 2 3 1 4 5 6 and I’ll define a function that access elements with a given row def … Read more
I have a large (about 12M rows) DataFrame df with say: df.columns = [‘word’,’documents’,’frequency’] So the following ran in a timely fashion: word_grouping = df[[‘word’,’frequency’]].groupby(‘word’) MaxFrequency_perWord = word_grouping[[‘frequency’]].max().reset_index() MaxFrequency_perWord.columns = [‘word’,’MaxFrequency’] However, this is taking an unexpectedly long time to run: Occurrences_of_Words = word_grouping[[‘word’]].count().reset_index() What am I doing wrong here? Is there a better way … Read more
I am kind of getting stuck on extracting value of one variable conditioning on another variable. For example, the following dataframe: A B p1 1 p1 2 p3 3 p2 4 How can I get the value of A when B=3? Every time when I extracted the value of A, I got an object, not … Read more