Letter Count on a string

Question

Python newb here  I m trying to count the number of letter  a s in a given string  Code is below  It keeps returning 1 instead 3 in string  banana   Any input appreciated    def count letters word  char       count   0     while count  lt   len word           for char in word              if char    word count                   count    1             return count    print count letters  banana   a

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count letters     number count letters count      print number

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A simple way is as follows   def count letters word  char       return word count char    Or  there s another way count each element directly   from collections import Counter Counter  banana     Of course  you can specify one element  e g   Counter  banana    a

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banana  count  ana   returns 1 instead of 2    I think the method iterates over the string  or the list  with a step equal to the length of the substring so it doesn t see this kind of stuff   So if you want a  full count  you have to implement your own counter with the correct loop of step 1  Correct me if I m wrong

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Alternatively You can use   mystring    banana  number   mystring count  a

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x str input  insert string    c 0 for i in x     if  a  in i        c c 1 print c

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You have a number of problems    There s a problem with your indentation as others already pointed out  There s no need to have nested loops  Just one loop is enough  You re using char to mean two different things  but the char variable in the for loop will overwrite the data from the parameter    This code fixes all these errors   def count letters word  char       count   0     for c in word          if char    c              count    1     return count   A much more concise way to write this is to use a generator expression   def count letters word  char       return sum char    c for c in word    Or just use the built-in method count that does this for you   print  abcbac  count  c

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I see a few things wrong    You reuse the identifier char  so that will cause issues  You re saying if char    word count  instead of word some index  You return after the first iteration of the for loop    You don t even need the while  If you rename the char param to search   for char in word      if char    search          count    1 return count

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Your return is in your for loop   Be careful with indentation  you want the line return count to be outside the loop   Because the for loop goes through all characters in word  the outer while loop is completely unneeded   A cleaned-up version   def count letters word  to find       count   0     for char in word          if char    to find              count    1     return count

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One problem is that you are using count to refer both to the position in the word that you are checking  and the number of char you have seen  and you are using char to refer both to the input character you are checking  and the current character in the string   Use separate variables instead     Also  move the return statement outside the loop  otherwise you will always return after checking the first character    Finally  you only need one loop to iterate over the string   Get rid of the outer while loop and you will not need to track the position in the string   Taking these suggestions  your code would look like this   def count letters word  char     count   0   for c in word      if char    c        count    1   return count

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The other answers show what s wrong with your code  But there s also a built-in way to do this  if you weren t just doing this for an exercise    gt  gt  gt   banana  count  a   3     Danben gave this corrected version   def count letters word  char     count   0   for c in word      if char    c        count    1   return count   Here are some other ways to do it  hopefully they will teach you more about Python   Similar  but shorter for loop  Exploits the fact that booleans can turn into 1 if true and 0 if false   def count letters word  char     count   0   for c in word      count     char    c    return count   Short for loops can generally be turned into list generator comprehensions  This creates a list of integers corresponding to each letter  with 0 if the letter doesn t match char and 1 if it does  and then sums them   def count letters word  char     return sum char    c for c in word    The next one filters out all the characters that don t match char  and counts how many are left   def count letters word  char     return len  c for c in word if c    char

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def count letter word  char       count   0     for char in word          if char    word              count    1     return count         Your return is inside your for loop r   count word  banana    a   print r                  3

[python] Letter Count on a string

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