select rows from a query in DataFrame in Pandas

Question

I'm sure what I'm asking is simple question but have yet to figure it out. I have a panda df and I want to run this basic query on it

Select a,b,c 
FROM TABLE
WHERE (TABLE.time >= x ) && (TABLE.time <= y)
GROUP BY c

so if I have a table

A    B    time

a    b    time1
c    d    time2
e    f    time3

I would want only to return the a,b,c where the time is greater or less than the ones in the query. Also would this query on a Dataframe give me another df if I assign the query to a variable say something like

df2 = df.query()

I hope this makes sense

you can actually use df.query in case you didn't know pandas.pydata.org/pandas-docs/version/0.22.0/generated/… — Yuca
– Yuca, Commented Sep 19, 2018 at 19:46
yes I've looked into df.query() but the first parameter of the function ask for a string but im not sure of the syntax here since its not the regular SQL query. Im pretty new to pandas so im not sure how to do this statement — Jeff Pernia
– Jeff Pernia, Commented Sep 19, 2018 at 19:55

Krishna · Accepted Answer · 2018-09-19 20:39:48Z

1

As mentioned in Documents docs

The query() method uses a slightly modified Python syntax by default. It is used to apply condition like greater then less then. query method does not support group by itself instead data frame have method groupby which works the same way.

I attempted to write code for your query take a look at it :

g= table.query('time>=x and time<y').groupby('C')

for name,group in g:
    print(name , group[['a','b','c']])

Without using query() :

g = table[(table.time>=x) & (table.time <= y)].groupby('C')

for name,group in g:
        print(name , group[['a','b','c']])

edited Sep 19, 2018 at 20:39

answered Sep 19, 2018 at 20:30

Krishna

1982 silver badges10 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Jeff Pernia · Accepted Answer · 2018-09-19 20:39:31Z

0

So i'm sure this isn't the best work-around but it worked for me.

df = pd.read_excel("file.xlsx", index_col= None, na_values=['NA'] , usecols=[18,4,5,21,0,1])
df2 = df[(df.TIME >= x) , (df.TIME <= y)]
df3 = df2[['a','b','c']]

That help me get the a,b,c within the time range I put

answered Sep 19, 2018 at 20:39

Jeff Pernia

792 silver badges14 bronze badges

Collectives™ on Stack Overflow

select rows from a query in DataFrame in Pandas

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related