When this value is evaluated, the semantics of Haskell no longer yield a meaningful value. In other words, further operations on the value cannot be defined in Haskell. Several ways exist to express bottoms in Haskell code. For instance, undefined is an easily called example of a bottom value.
Various ways to iterate over sequences The sequence functions illustrated in 4. We can randomize the contents of a list s before iterating over them, using random. We can convert between these sequence types. For example, tuple s converts any kind of sequence into a tuple, and list s converts any kind of sequence into a list.
We can convert a list of strings to a single string using the join function, e. Some other objects, such as a FreqDist, can be converted into a sequence using list or sorted and support iteration, e. We can omit the parentheses because the comma has higher precedence than assignment.
It is equivalent to the following traditional way of doing such tasks that does not use tuples notice that this method needs a temporary variable tmp. There are also functions that modify the structure of a sequence and which can be handy for language processing. Thus, zip takes the items of two or more sequences and "zips" them together into a single list of tuples.
Given a sequence s, enumerate s returns pairs consisting of an index and the item at that index.
For some NLP tasks it is necessary to cut up a sequence into two or more parts. To do this we decide the location where we want to cut the datathen cut the sequence at that location. We can also verify that the ratio of the sizes of the two pieces is what we intended. Combining Different Sequence Types Let's combine our knowledge of these three sequence types, together with list comprehensions, to perform the task of sorting the words in a string by their length.
A simple string is actually an object with methods defined on it such as split. We use a list comprehension to build a list of tupleswhere each tuple consists of a number the word length and the word, e.
We use the sort method to sort the list in-place. Finally, we discard the length information and join the words back into a single string. The underscore is just a regular Python variable, but we can use underscore by convention to indicate that we will not use its value. We began by talking about the commonalities in these sequence types, but the above code illustrates important differences in their roles.
First, strings appear at the beginning and the end: Lists and tuples are used in the middle, but for different purposes.
A list is typically a sequence of objects all having the same type, of arbitrary length. We often use lists to hold sequences of words. In contrast, a tuple is typically a collection of objects of different types, of fixed length.
We often use a tuple to hold a record, a collection of different fields relating to some entity. This distinction between the use of lists and tuples takes some getting used to, so here is another example: An individual entry is represented as a tuple because it is a collection of objects with different interpretations, such as the orthographic form, the part of speech, and the pronunciations represented in the SAMPA computer-readable phonetic alphabet http: Note that these pronunciations are stored using a list.
Note A good way to decide when to use tuples vs lists is to ask whether the interpretation of an item depends on its position. For example, a tagged token combines two strings having different interpretation, and we choose to interpret the first item as the token and the second item as the tag.
Thus we use tuples like this: In contrast, the elements of a text are all tokens, and position is not significant. Thus we use lists like this: The linguistic meaning of the words might be different, but the interpretation of list items as tokens is unchanged.
The distinction between lists and tuples has been described in terms of usage. However, there is a more fundamental difference: In other words, lists can be modified, while tuples cannot.S n is the sum of the numbers to n.
Because we find that Δ 2 produces constant values, we assume the formula for the sum of the natural numbers is a quadratic, of the form an 2 +bn+c.
Using our values, we substitute 0, 1, and 3 in the Equation: [As a word to the wise, the constant value in the. Program to find the sum of first n natural numbers. We will see two C programs to calculate the sum of natural numbers. In the first C program we are using for loop for find the sum and in the second program we are doing the same using while loop.
This C# Program Generates the Sum of N vetconnexx.com C# program obtains the Nth number from the user and calculates its sum till the Nth number.
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By now you will have a sense of the capabilities of the Python programming language for processing natural language. How can I work with complex numbers in C? I see there is a complex.h header file, but it doesn't give me much information about how to use it.
How to access real and imaginary parts in an efficient way? Is there native functions to get module and phase? Candidjava Beginners Java program to find sum of first n natural numbers. Java program to find sum of first n numbers. By candid | Posted: 6 Mar, | Updated: 21 Dec, Code.
Java program to sum of odd numbers between 1