TensorFlow 1 version View source on GitHub

String lengths of input.

    input, unit='BYTE', name=None

Used in the notebooks

Used in the tutorials

Computes the length of each string given in the input tensor.

strings = tf.constant(['Hello','TensorFlow', '\U0001F642']) 
tf.strings.length(strings).numpy() # default counts bytes 
array([ 5, 10, 4], dtype=int32) 
tf.strings.length(strings, unit="UTF8_CHAR").numpy() 
array([ 5, 10, 1], dtype=int32) 


  • input: A Tensor of type string. The strings for which to compute the length for each element.
  • unit: An optional string from: "BYTE", "UTF8_CHAR". Defaults to "BYTE". The unit that is counted to compute string length. One of: "BYTE" (for the number of bytes in each string) or "UTF8_CHAR" (for the number of UTF-8 encoded Unicode code points in each string). Results are undefined if unit=UTF8_CHAR and the input strings do not contain structurally valid UTF-8.
  • name: A name for the operation (optional).


A Tensor of type int32.