使用多个 loc()

Question

Im trying to use multiple loc() on the below table but unfortunately the code is giving me an error stating:

ValueError: The truth value of a DataFrame is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().

my df is the following:

REFERENCE     PERIOD      QTY      PRICE
abc123        Jan-20       20       21.2
abc123        Feb-20      -40       22.3
abc123        Mar-20       20       22.9
cde456        Aug-20      -10       18.7
cde456        Sep-20       20       19.4
cde456        Jan-20      -10       19.93

The code giving me an error should ideally return a subset of the table:

dfa = df.loc[df['PERIOD'].str.contains(pat='JAN')] and df.loc[df['REFERENCE'].str.contains(pat='abc')]

Any ideas how what im doing wrong to use 2 .loc functions in the same string?

Thx

Answer 1

Try single loc with boolean operator:

df.loc[df['PERIOD'].str.contains('JAN') & 
       df['REFERENCE'].str.contains('A')]

Answer 2

You can give two conditions by separating them with & . Therefore, you don't need to use two .loc .

With .loc

df.loc[(df['PERIOD'].str.contains('Jan')) & (df['REFERENCE'].str.contains('abc'))]

Or

Without .loc

df[(df['PERIOD'].str.contains('Jan')) & (df['REFERENCE'].str.contains('abc'))]

Output:

   REFERENCE  PERIOD  QTY  PRICE
0    abc123  Jan-20   20   21.2