In python 3.5, how do I compare a string variable with part of another string?

Question

I'm currently learning Python and I have a question which I cannot find the answer too, currently I am trying to take a string variable given from the user and comparing it to part of another string. I want something like this:

Program: The given sentence is "I like chemistry", enter a word in the sentence given.

User: like

Program: Your word is in the sentence.

I can only seem to make a program using the if function and == but this only seems to recognize that the two strings are similar if I type the full sentence given by the program.

From the some of the answers I have changed my program to but there seems to be an error I cannot find.

sentence=("I like chemistry")
print("The given sentence is: ",sentence)
word=input("Give a word in the sentence: ").upper
while word not in sentence:
    word=input("Give a valid word in the sentence: ")
if word in sentence:
    print("valid")

You want to test whether the word is **in** the sentence. Have you tried `if word in sentence`? — tobias_k, May 12 '16 at 16:12
Any word, as in the user can type in "like" for the given sentence and the program would tell you it is a match. — python_learner, May 12 '16 at 16:13
"I can only seem to make a program using" do you mean that that's the only thing you can think of, or is the assignment (?) restricted to using those operations? — tobias_k, May 12 '16 at 16:14
Part of programming is to understand *all* of the constraints of a problem. For example in this one, should a search for "lick" also match "clicked"? — Mark Ransom, May 12 '16 at 16:30

score 1 · Answer 1 · answered May 12 '16 at 16:14

You could use in together with split:

>>> s = "I like chemistry"
>>> words = s.split()
>>> "like" in words
True
>>> "hate" in words
False

The difference between this approach vs. using in against the non-split string is like this:

>>> "mist" in s
True
>>> "mist" in words
False

If you want arbitrary substrings then use simply w in s but is you want white-space delimited words then use w in words.

score 0 · Answer 2 · answered May 12 '16 at 16:13

0

if word in sentence:

Welcome to the wonderful world of python.

answered May 12 '16 at 16:13

polku

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score 0 · Answer 3 · answered May 12 '16 at 16:14

0

In Python you use if substring in string: ....

Example:

mystring = "I like chemistry"
if "like" in mystring:
    print("Word is in sentence")
else:
    print("Word is not in sentence")

Hope this helps!

answered May 12 '16 at 16:14

linusg

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score 0 · Answer 4 · answered May 12 '16 at 16:22

Instead of thinking it as finding a substring, think it as checking membership. And all sequence types in Python expose the same interface for that purpose. Say s is a sequence, i.e str, list, tuple and to see if m is in s,

>>> m in s # => bool :: True | False

The same in operator works for dict keys and set as well, though they are not sequences.

In python 3.5, how do I compare a string variable with part of another string?

4 Answers4