How to print values in dataframes column by their indexes?-CodePudding

I have a dataframe:

                              value
id  
742                            aa
1711                           bb
1731                           qq
1799                           ff
2741                           pp

id is index column. I want to print only those values from column "value" which are in this list: [742, 1731, 1799]. So the output must be:

aa
qq
ff

How to do that?

I tried this:

for i in [742, 1731, 1799]:
    print(df[df.index == i]["value"])

but the output is:

value
742    aa
Name: value, dtype: object
value
1731    qq
Name: value, dtype: object
value
1799    ff
Name: value, dtype: object

CodePudding user response：

This should do it:

Restating the problem:

ids = [
    {"id":"742", "value":"aa"},
    {"id":"1711", "value":"bb"}, 
    {"id":"1731", "value":"qq"}, 
    {"id":"1799", "value":"ff"}, 
    {"id":"2741", "value":"pp"}]

df = pd.DataFrame(data=ids)
df = df.set_index(["id"])

This gets you the filtered list:

filtered_df = df[df.index.isin(["742","1731","1799"])]

CodePudding user response：

Use .set_index to declare 'id' as the index, then .loc[...] to specify the list of indices you're interested in.

df = pd.DataFrame({'id': [8, 13, 21, 34, 55, 89], 'val': 'for sale baby shoes never worn'.split()}).set_index('id')

print(df)
#       val
# id       
# 8     for
# 13   sale
# 21   baby
# 34  shoes
# 55  never
# 89   worn

print(df.loc[[13,89]])
#      val
# id      
# 13  sale
# 89  worn

CodePudding user response：

for i in df:
    if i.index in [742, 1731, 1799]:
        # print(i.value)
        # print(i["value"])