I am a beginner in python, I am looking for a function that can tell me the number of integers in a given list. For example:
list = [1, 2, 4.5, 6, 8.3, 9]
print(int_num(list))
output
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Stack Overflow is not a place to request a function. Here you present your function which does not work as expected. – Klaus D. May 01 '21 at 04:01
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1@Klaus No, not all questions need to be debugging questions. How-to questions are perfectly fine. E.g. [How can I count the occurrences of a list item?](https://stackoverflow.com/q/2600191/4518341) – wjandrea May 01 '21 at 04:11
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@wjandrea That's not a how-to question. – Klaus D. May 01 '21 at 04:14
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1@Klaus What do you mean? It doesn't literally say "how to", but you could easily rephrase it as "How to count the occurrences of a list item?" – wjandrea May 01 '21 at 04:15
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@wjandrea Well, following that logic, any "question" trying to outsource homework is also a how-to question. Or in other words: the question here is missing any effort to solve the problem. – Klaus D. May 01 '21 at 04:21
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1@KlausD. The problem with do my homework questions is that they aren't generally applicable to multiple situations or future visitors. A simple task such as this question can be. – duckboycool May 01 '21 at 04:22
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@duckboycool Exactly. See for example this Meta discussion: [Why is “Can someone help me?” not an actual question?](https://meta.stackoverflow.com/q/284236/4518341) – wjandrea May 01 '21 at 04:25
2 Answers
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def isInt(x):
if isinstance(x, int):
return True
else:
return False
ls = [1,2,4.5,6,8.3,9]
# Note filter function is used to filter out elements that do not satisy the function in our case it is isInt
# filter function gives a filter object cast it to a list
filtered = list(filter(isInt, ls))
print(filtered)
print(len(filtered))
Chetan Jain
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You wrote a whole function to wrap a simple built-in function, and included a control structure to wrap the return value of the call. Seriously? – Klaus D. May 01 '21 at 04:17
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Building a new list is unnecessary. You can do `sum(isinstance(x, int) for x in ls)`, since `True` will be coerced to `1` and `False` to `0`. – wjandrea May 01 '21 at 04:17
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But FWIW, the if-statement is also unnecessary. Instead, `return isinstance(x, int)` – wjandrea May 01 '21 at 04:19
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Also, `filter` is not a function, and it returns a `filter` object, not a list. – wjandrea May 01 '21 at 04:22
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There is already a built-in function len(), that, if required, can be wrapped in your own custom function
list = [1, 2, 3, 4]
print(len(list))
Dugbug
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