Stat 133代写、代做R编程设计、代写Regular Expressions、代做R语言

日期：2018-11-15 10:28

Warm-Up 07: Regular Expressions

Stat 133, Fall 2018, Prof. Sanchez

Due date: Nov-13 (before midnight)

The main purpose of this assignment is to work with strings. More especifically, you will

practice with some basic/intermediate manipulations of strings and regular expressions.

General Instructions

Write your narrative and code in an Rmd (R markdown) file.

Name this file as warmup07-first-last.Rmd, where first and last are your first and

last names (e.g. warmup07-gaston-sanchez.Rmd).

Submit your Rmd and html files to bCourses.

Data “Emotion in Text”

You’ll be working with the data file text-emotion.csv available in the course github

repository. The original source is the data set “Emotion in Text” from the website Crowd

Flower Data for Everyone https://www.crowdflower.com/data-for-everyone/

The file contains four columns:

tweet_id: tweet identifier

sentiment: class or sentiment label

author: username author of the tweet

content: content of the tweet

In your Rmd file write R code to do computations in order to answer each of the

following questions

1) Number of characters per tweet

Count the number of characters in the tweet contents; create a vector for this purpose.

It is possible that you find tweets containing more than 140 characters. This has to do

with the so-called predefined XML entities such as

– & which represents an ampersand &

– " which represent quotes "

– &lt; which represents less-than symbol <

– &gt; which represents greater-than symbol >

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Display the summary() of the vector obtained above.

Likewise, graph a histogram of these counts. To plot the histogram, use a bin width of 5

units: 1-5, 6-10, 11-15, 16-20, etc. In other words: the first bin involves tweets between

1 and 5 characters (inclusive), the second bin involves tweets containing between 6 and

10 characters (inclusive), and so on.

Are there any tweets with 0 characters? (write a command that answers this question).

Are there any tweets with 1 character? If yes (write commands that answer these

questions):

– how many?

– what is their content?

– what is their location (i.e. index or position)?

What is the tweet with the most characters (i.e. max length)? (write a command that

answers these questions).

– the number of characters

– display its content

– what is its location (i.e. index or position)?

2) Sentiment

What are the different types of sentiments (i.e. categories)? (write a command that

answers this question)

Compute the frequencies (i.e. counts) of each sentiment (and display these frequencies).

Graph the relative frequencies (i.e. proportions) with a horizontal barplot (bars horizontally

oriented) in decreasing order, including names of sentiment types.

Sentiment and length of tweets: compute a table with the average length of characters

per sentiment (i.e. average number of characters for neutral tweets, for happy tweets,

etc.). Display this table.

3) Author (usernames)

According to Twitter, usernames:

cannot be longer than 15 characters

can only contain alphanumeric characters (letters A-Z, numbers 0-9) with the exception

of underscores (i.e. cannot contain any symbols, dashes or spaces, except underscores)

If you want to know more about twitter usernames, visit:

https://help.twitter.com/en/managing-your-account/twitter-username-rules

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Confirm that the values in column author follow each of the rules for valid usernames:

No longer than 15 characters (if you find usernames longer than 15 characters, display

them)

Contain alphanumeric characters and underscores (if you find usernames containing

other symbols, display them)

What is the number of characters of the shortest usernames? And what are the names

of these authors? (write commands to answer these questions)

4) Various Symbols and Strings

How many tweets contain at least one caret symbol "?" (write a command to answer

this question).

How many tweets contain three or more consecutive dollar symbols "$" (write a

command to answer this question).

How many tweets do NOT contain the characters "a" or "A" (write a command to

answer this question).

Display the first 10 elements of the tweets that do NOT contain the characters "a" or

"A" (write a command to answer this question).

Number of exclamation symbols "!": compute a vector with the number of exclamation

symbols in each tweet, and display its summary().

What’s the tweet (content) with the largest number of exclamation symbols ! Display

its content. (write a command to answer this question)

How many tweets contain the individual strings "omg" or "OMG" (write a command to

answer this question). For example:

– omg I just saw them again (this would be a match)

– OMG I just saw them again (this would be a match)

– I just saw them again omg (this would be a match)

– I just saw them again OMG (this would be a match)

– I just saw them omg can't believe it (this would be a match)

– I just saw them OMG can't believe it (this would be a match)

– omg: I just saw them again (this would NOT be a match)

– OMG,I just saw them again (this would NOT be a match)

– I just saw them again omg!!! (this would NOT be a match)

– I just saw them again omgomgomg (this would NOT be a match)

– I just saw them again lol-omg!!! (this would NOT be a match)

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5) Table of Average Number of Patterns by Sentiment

Write code to create (and display) a table (e.g. data frame, tibble, matrix) in which the rows

correspond to the unique types of sentiments, and the columns correspond to:

1. average number of lower case letters

2. average number of upper case letters

3. average number of digits

4. average number of punctuation symbols

5. average number of spaces

Hint: POSIX character classes are your friends (e.g. "[[:xdigit:]]").