Python: Do Not Exclude Rows After Map(dictionary)

I want to use a dictionary in order to create a new field/column in a dataframe. If the values don't match, I want the value to be set to 'NA' or something similar. So, I am using

Solution 1:

Several questions here:

(1) na_action

na_action relates to the input not the output. Here is an example lifted from pandas documentation:

>>> s = pd.Series([1, 2, 3, np.nan])
>>> s2 = s.map('this is a string {}'.format, na_action=None)
0    this is a string 1.0
1    this is a string 2.0
2    this is a string 3.0
3    this is a string nan
dtype: object

>>> s3 = s.map('this is a string {}'.format, na_action='ignore')
0    this is a string 1.0
1    this is a string 2.0
2    this is a string 3.0
3                     NaN
dtype: object

(2) How to keep rows if no match?

This may be what you are looking for. If it can't find a match, it won't change.

b = d.replace(dictionary)

(3) Print rows where Country_Code does not have a match in dictionary.

df[~df['Country_Code'].isin(dictionary)]

Solution 2:

You can see the docs regarding the difference.

As for the desired result I suggest apply:

a = s.apply(lambda x: dictionary[x] if x in dictionary else x)