Paste Strings Without Spaces in R

  1. Remove Spaces When Merging Strings in R
  2. Base R Functions
  3. Conclusion

This article will explore three ways to remove spaces when merging (concatenating) strings.

Remove Spaces When Merging Strings in R

We will use individual strings, vectors of strings, and a data frame with strings for the demonstrations.

Example Code:

# The individual strings.
s1 = "The sky"
s2 = "is blue."
s1a = " The sky "
s2a = " is blue. "

# Columns for the data frame.
C1 = c("The sky", " The earth ")
C2 = c("is blue.", " is green. ")
# The data frame.
dtfr = data.frame(Col1=C1, Col2=C2)

Base R Functions

The following base R functions can be used to remove spaces from strings.

Use the paste() Function With sep="" to Remove Spaces

When pasting strings, R adds a space in between. We can use sep=""to remove the added space.

In the context of vectors of the same length, paste() merges corresponding elements of the vectors. To merge all output elements into one long string without added spaces, we can use collapse="".

To merge data frame columns without added spaces, use sep="".

Example Code:

# MERGE WITH paste()

# Default: adds space.
paste(s1, s2)

# Remove added space.
paste(s1, s2, sep="")

# Does not remove existing spaces.
# Variables s1a and s2a have space characters at the beginning and end.
paste(s1a, s2a, sep="")

# Element-wise merging of vectors.
# No spaces are added in between.
paste(C1, C2, sep="")

# After element-wise merging, we can
# collapse all the elements of the result into a single string.
paste(C1, C2, sep="", collapse="")

# Merge columns of a data frame.
# No spaces are added in between.
dtfr$Mr = paste(dtfr$Col1, dtfr$Col2, sep="")
dtfr

Output:

> # Default: adds space.
> paste(s1, s2)
[1] "The sky is blue."

> # Remove added space.
> paste(s1, s2, sep="")
[1] "The skyis blue."

> # Does not remove existing spaces.
> # Variables s1a and s2a have space characters at the beginning and end.
> paste(s1a, s2a, sep="")
[1] " The sky  is blue. "

> # Element-wise merging of vectors.
> # No spaces are added in between.
> paste(C1, C2, sep="")
[1] "The skyis blue."        " The earth  is green. "

> # After element-wise merging, we can
> # collapse all the elements of the result into a single string.
> paste(C1, C2, sep="", collapse="")
[1] "The skyis blue. The earth  is green. "

> # Merge columns of a data frame.
> # No spaces are added in between.
> dtfr$Mr = paste(dtfr$Col1, dtfr$Col2, sep="")
> dtfr
         Col1        Col2                     Mr
1     The sky    is blue.        The skyis blue.
2  The earth   is green.   The earth  is green.

Use the trimws() and paste() Functions to Remove Spaces

The trimws() function can remove whitespace from the left, right, or both sides of a string. Besides space characters, other characters considered whitespace include the horizontal tab, carriage return and new line characters.

By default, this function removes all whitespace from both sides of a string.

Syntax:

trimws(string, which="side", whitespace="[ \t\r\n]")
# where `side` can be `left` or `right` or `both`

Example Code:

# trimws() removes spaces from the left, right or both
trimws(s2a, which="left", whitespace=" ")
trimws(s2a, which="right", whitespace=" ")
trimws(s2a, which="both", whitespace=" ")
# By default, it removes all whitespace from both sides.
s2a
trimws(s2a)

# Remove leading, trailing and added spaces when merging vectors.
paste(trimws(C1), trimws(C2), sep="")

# Remove leading, trailing and added spaces when combining columns of a data frame.
dtfr$Mr2 = paste(trimws(dtfr$Col1), trimws(dtfr$Col2), sep="")
dtfr

Output:

> # trimws() removes spaces from the left, right or both
> trimws(s2a, which="left", whitespace=" ")
[1] "is blue. "
> trimws(s2a, which="right", whitespace=" ")
[1] " is blue."
> trimws(s2a, which="both", whitespace=" ")
[1] "is blue."

> # By default, it removes all whitespace from both sides.
> s2a
[1] " is blue. "
> trimws(s2a)
[1] "is blue."

> # Remove leading, trailing and added spaces when merging vectors.
> paste(trimws(C1), trimws(C2), sep="")
[1] "The skyis blue."    "The earthis green."

> # Remove leading, trailing and added spaces when combining columns of a data frame.
> dtfr$Mr2 = paste(trimws(dtfr$Col1), trimws(dtfr$Col2), sep="")
> dtfr
         Col1        Col2                     Mr                Mr2
1     The sky    is blue.        The skyis blue.    The skyis blue.
2  The earth   is green.   The earth  is green.  The earthis green.

We first used trimws() to remove spaces from both sides of strings before merging them using the paste() function.

Use the gsub() and paste() Functions to Remove Spaces

Syntax:

gsub(search_for, replace_with, string)

Example Code:

# For vectors: merge strings and remove all spaces from the result.
gsub(" ", "", paste(C1, C2))

# For data frame: merge string columns of a data frame and remove all spaces.
dtfr$Mr3 = gsub(" ", "", paste(dtfr$Col1, dtfr$Col2))
dtfr

Output:

> # For vectors: merge strings and remove all spaces from the result.
> gsub(" ", "", paste(C1, C2))
[1] "Theskyisblue."    "Theearthisgreen."

> # For data frame: merge string columns of a data frame and remove all spaces.
> dtfr$Mr3 = gsub(" ", "", paste(dtfr$Col1, dtfr$Col2))
> dtfr
         Col1        Col2                     Mr                Mr2              Mr3
1     The sky    is blue.        The skyis blue.    The skyis blue.    Theskyisblue.
2  The earth   is green.   The earth  is green.  The earthis green. Theearthisgreen.

We first merge the strings using paste() and then remove all spaces using gsub().

Use the stringr Package and paste() Function to Remove Spaces

Syntax:

str_replace_all(string, search_for, replace_with)

Example Code:

# Install the stringr package.
# install.packages("stringr")
# Load the stringr package.
library(stringr)

# With vectors.
str_replace_all(paste(C1, C2), " ", "")

# With columns of a data frame.
# We will first recreate the dataframe to improve readability.
dtfr = data.frame(Col1=C1, Col2=C2)

# Use the str_replace_all() function.
dtfr$StrRplAll = str_replace_all(paste(dtfr$Col1, dtfr$Col2), " ", "")
dtfr

Output:

> # Load the stringr package.
> library(stringr)

> # With vectors.
> str_replace_all(paste(C1, C2), " ", "")
[1] "Theskyisblue."    "Theearthisgreen."

> # With columns of a data frame.
> # We will first recreate the dataframe to improve readability.
> dtfr = data.frame(Col1=C1, Col2=C2)

> # Use the str_replace_all() function.
> dtfr$StrRplAll = str_replace_all(paste(dtfr$Col1, dtfr$Col2), " ", "")
> dtfr
         Col1        Col2        StrRplAll
1     The sky    is blue.    Theskyisblue.
2  The earth   is green.  Theearthisgreen.

The stringr package of R’s tidyverse is built on top of the stringi package. This package provides the str_replace_all() function, which is similar to the gsub() function.

Conclusion

This article showed how to remove the following:

  • Spaces are added when merging strings with the paste() function.
  • Leading and trailing spaces from strings.
  • All spaces from a string.

The functions can be combined/nested depending on the need to get the desired output.

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