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stringr::str_length() 

str_length(string)
Returns: integer · Updated March 16, 2026 · Tidyverse
stringr string length tidyverse

The str_length() function from stringr returns the number of characters in a string. Unlike base R’s nchar(), this function consistently handles NA values and uses UTF-8 encoding by default, making it more predictable for modern text processing workflows.

Syntax

str_length(string)

Parameters

ParameterTypeDescription
stringcharacterA character vector

Examples

Basic usage

library(stringr)

# Get length of individual strings
str_length("hello")
# [1] 5

# Vectorized over multiple strings
str_length(c("apple", "banana", "cherry"))
# [1] 5 6 6

Handling NA values

# NA is preserved (unlike nchar which may warn)
str_length(c("hello", NA, "world"))
# [1]  5 NA  5

# Compare with base R behavior
nchar(c("hello", NA, "world"))
# [1]  5 NA  6

Working with empty and whitespace strings

# Empty string has zero length
str_length("")
# [1] 0

# Whitespace characters are counted
str_length("  ")
# [1] 2

# Newlines and tabs count as single characters
str_length("a\nb")
# [1] 3
str_length("a\tb")
# [1] 3

Using with dplyr pipelines

library(dplyr)

df <- data.frame(
  word = c("apple", "banana", "cherry", "date", "elderberry")
)

df %>%
  mutate(char_count = str_length(word))
#          word char_count
# 1      apple          5
# 2     banana          6
# 3     cherry          6
# 4        date          4
# 5 elderberry         10

Counting characters in sentences

sentences <- c(
  "The quick brown fox.",
  "Hello, world!",
  "R is great."
)

# Get lengths of each sentence
str_length(sentences)
# [1] 20 13 11

# Find the longest sentence
longest <- sentences[which.max(str_length(sentences))]
longest
# [1] "The quick brown fox."

UTF-8 and special characters

# Emoji count as single characters
str_length("🔥")
# [1] 1

# Combined characters
str_length("é")        # Single codepoint
# [1] 1

str_length("e\u0301")  # e + combining accent
# [1] 2

# Non-Latin scripts
str_length("日本語")
# [1] 3

Filtering by string length

library(dplyr)

words <- data.frame(
  term = c("a", "at", "cat", "cats", "caterpillar")
)

# Keep only words with 3-5 characters
words %>%
  filter(between(str_length(term), 3, 5))
#         term
# 1        cat
# 2       cats

Common Patterns

  • With dplyr::mutate: Add character count columns
  • With dplyr::filter: Filter rows by string length
  • With dplyr::arrange: Sort by string length
  • With max() / min(): Find longest or shortest strings

Summary statistics

text_data <- c("short", "medium length", "this is a longer string", "tiny")

# Character length statistics
c(
  min = min(str_length(text_data)),
  max = max(str_length(text_data)),
  mean = mean(str_length(text_data))
)
#  min  max mean 
#    5   20 11.5

Combined with other stringr functions

# Get only strings longer than 5 characters
words <- c("a", "at", "cat", "cats", "caterpillar")
words[str_length(words) > 5]
# [1] "caterpillar"

# Pad all strings to minimum length
str_pad(words, width = max(str_length(words)), side = "right")
# [1] "a          " "at         " "cat        " "cats       " "caterpillar"

See Also