Pandas Dataframe - finding occurrences of a string in a string

Question

I have a dataframe that looks like this (but longer):

    Letter  Password
0   l       klfbblslvjclmlnqklvg
1   h       pghjchdxhnjhjd

How do I count the number of occurences of Letter in Password? Such that it is 6 for the first row and 4 for the second row.

This does not work, because count needs a regex:

df['Occurrences'] = df['Password'].str.count(df['Letter']).astype(int)

How can I do it then?

Quang Hoang · Accepted Answer · 2020-12-21 21:54:42Z

2

This case, you can use apply:

df['Occurrences'] = df.apply(lambda x: x['Password'].count(x['Letter']), axis=1)

Output:

  Letter              Password  Occurrences
0      l  klfbblslvjclmlnqklvg            6
1      h        pghjchdxhnjhjd            4

answered Dec 21, 2020 at 21:54

Quang Hoang

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1 Comment

Thank you, this works great. I will surely get more use out of the apply function in the future!

Dani Mesejo · Accepted Answer · 2020-12-21 21:45:39Z

1

You could do:

df['Occurrences'] = [pas.count(letter) for pas, letter in zip(df['Password'], df['Letter'])]
print(df)

Output

  Letter              Password  Occurrences
0      l  klfbblslvjclmlnqklvg            6
1      h        pghjchdxhnjhjd            4

answered Dec 21, 2020 at 21:45

Dani Mesejo

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