to_s method is define in Object class and hence all ruby objects have method to_s . Certain methods always call to_s method. For example when we do string interpolation then to_s method is called. to_s is simply the string representation of the object. Before we look at to_str let’s see a case where ruby raises error.

When you call a function with an argument of the wrong type, R will try to coerce values to a different type so that the function will work. Values are converted to the simplest type required to represent all information. The ordering is roughly logical < integer < numeric < complex < character < list.

Type coercion is the changing of an object’s type into another type, together with its value. For example, changing an Integer into a String with #to_s or a Float into an Integer with #to_i . Let’s first look at how we usually coerce values to different types in Ruby with explicit casting helpers.

The to_a() is an inbuilt method in Ruby returns an array containing the numbers in the given range. Syntax: range1.to_a() Parameters: The function accepts no parameter. Return Value: It returns an array containing all the numbers.

There is no substring method in Ruby. Instead we rely upon ranges and expressions. Substring ranges. With a range, we use periods in between 2 numbers—the first and last index of the substring.

Strings exist within either single quotes ‘ or double quotes ” in Ruby, so to create a string, enclose a sequence of characters in one or the other: ‘This is a string in single quotes. ‘ “This is a string in double quotes.”

Strip. The . strip method removes the leading and trailing whitespace on strings, including tabs, newlines, and carriage returns ( /t , /n , /r ).

If you need to remove more than one character then chomp is your best bet. This is what the ruby docs have to say about chop : Returns a new String with the last character removed. If the string ends with /r/n, both characters are removed.

How to remove a particular character from a string ?

1. public class RemoveChar {
2. public static void main(String[] args) {
3. String str = “India is my country”;
4. System.out.println(charRemoveAt(str, 7));
5. }
6. public static String charRemoveAt(String str, int p) {
7. return str.substring(0, p) + str.substring(p + 1);
8. }

Delete – (. Delete is the most familiar Ruby method, and it does exactly what you would think: deletes a sub-string from a string. It will search the whole string and remove all characters that match your substring. The downside of delete is that it can only be used with strings, not RegExs.

The delete method accepts ranges with – and negations with ^ (similar to a regex) so you can do something like this: a. delete! “^A-Za-z ” . You could also use regular expressions as shown by @arieljuod.

The difference is that sub only replaces the first occurrence of the pattern specified, whereas gsub does it for all occurrences (that is, it replaces globally). sub and gsub perform replacement of the first and all matches respectively.

gsub! is a String class method in Ruby which is used to return a copy of the given string with all occurrences of pattern substituted for the second argument. If no substitutions were performed, then it will return nil. If no block and no replacement is given, an enumerator is returned instead.

1 Answer

1. To remove all special characters from a string, you can use the string_replace_all function from the stringr package as follows:
2. To remove all the punctuation characters:
3. To remove all the non-alphanumeric characters:
4. You can also use the gsub function from the base package as follows:

R has some handy, built-in functions to take care of that. The trimws() function will remove leading or trailing spaces in a string….For example, here is a string with an extra space at the beginning and the end:

1. sentenceString <- ‘ Dan is here. ‘
2. sentenceString = trimws(sentenceString)
3. sentenceString.

The r means that the string is to be treated as a raw string, which means all escape codes will be ignored. “String literals may optionally be prefixed with a letter ‘r’ or ‘R’; such strings are called raw strings and use different rules for interpreting backslash escape sequences. “

The sub() function (short for substitute) in R searches for a pattern in text and replaces this pattern with replacement text. You use sub() to substitute text for text, and you use its cousin gsub() to substitute all occurrences of a pattern.

To replace NA with 0 in an R data frame, use is.na() function and then select all those values with NA and assign them to 0. myDataframe is the data frame in which you would like replace all NAs with 0.

This error usually occurs when a package has not been loaded into R via library, so R does not know where to find the specified function. It’s a good habit to use the library functions on all of the packages you will be using in the top R chunk in your R Markdown file, which is usually given the chunk name setup.

To extract a substring from a string according to a pattern, you can use the following functions:

1. string = c(“G1:E001”, “G2:E002”, “G3:E003”) substring(string, 4)
2. substring(string, regexpr(“:”, string) + 1) [1] “E001” “E002” “E003”
3. library(dplyr) library(tidyr)
4. library(“stringr”)