How to find a letter in a string in Python

Question

Find out if word 'dog' is in a string.

I tried doing this code and i dont know where the error is .

y='dogaway'
for i in range(len(y)):
    if y[i:i+2]=='dog':
        x=x+1
print(x)

I expected output to be 1 but the actual ouput is 0.

`my_str.find('dog')` will return the index if it is in the `str`. — Error - Syntactical Remorse, Jun 21 '19 at 13:00

Error - Syntactical Remorse · Answer 1 · 2019-06-21T13:12:15.227

1

You can use count.

y = 'dogaway'
print(y.count('dog')) # Outputs 1

or if you want to fix your code, you are just off by one in your splice:

y = 'dogaway'
x = 0
for i in range(len(y) - 3): # Make sure your range accounts for the look ahead
    # In the future add a print to make sure it is doing what you expect:
    # print(y[i:i + 2])
    if y[i:i + 3] == 'dog': # Here you were off by 1
        x = x + 1
print(x)

edited Jun 21 '19 at 13:12

answered Jun 21 '19 at 13:04

Error - Syntactical Remorse

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Thank you! your fix really helped me. I do now remind that in slicing y[x:y] , it goes from including x upto y (but not including it). – Dilshan Sandhu Jun 21 '19 at 13:11
@DilshanSandhu If it answered your question don't forget to mark it as an answer. It helps :) – Error - Syntactical Remorse Jun 21 '19 at 13:11

score 0 · Answer 2 · answered Jun 21 '19 at 13:01

0

Even simpler:

if 'dog' in y:
    ...

answered Jun 21 '19 at 13:01

nKn

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This doesn't give the expected output. – Sayse Jun 21 '19 at 13:02
As I see your comment is being upvoted, I refer to the same comment on the other answer: You don't know if this is the expected output, as the "1" might only be a flag to check if the containing code is or not working. This *does* what the OP is asking: "Find out if word 'dog' is in a string." – nKn Jun 21 '19 at 13:48

Felipe Sulser · Accepted Answer · 2019-06-21T13:02:48.170

-2

You can use the in membership operator in Python.

'dog' in 'dogaway'

returns True

edited Jun 21 '19 at 13:02

answered Jun 21 '19 at 13:02

Felipe Sulser

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1

This doesn't give the expected output. – Sayse Jun 21 '19 at 13:02
2

He wants to find out if the word dog is in the string I don't the think 1 is that important – Jun 21 '19 at 13:03
1

If what you want is 0 or 1 just do `int('dog' in 'dogaway')` – Felipe Sulser Jun 21 '19 at 13:04
@JonathanDyke - From the given information, that is impossible to know why it is the expected output and what they intend to do with it – Sayse Jun 21 '19 at 13:07
1

@Sayse then how do you know it's not the expected output? – nKn Jun 21 '19 at 13:09
"I expected output to be 1" is pretty explicit – Sayse Jun 21 '19 at 13:10
It doesn't mean he wants to do anything with that "1", maybe he's just a Python newbie and is trying to do basic operations. The first sentence is pretty explicit as well ("Find out if word 'dog' is in a string."). – nKn Jun 21 '19 at 13:12
2

The question is: How to find a letter in a string in Python. Does the provided answer not bring a solution to that? – Felipe Sulser Jun 21 '19 at 13:13

How to find a letter in a string in Python

3 Answers3