NumPy - String Functions


The following functions are used to perform vectorized string operations for arrays of dtype numpy.string_ or numpy.unicode_. They are based on the standard string functions in Python's built-in library.

Sr.No. Function & Description
1 add()

Returns element-wise string concatenation for two arrays of str or Unicode

2 multiply()

Returns the string with multiple concatenation, element-wise

3 center()

Returns a copy of the given string with elements centered in a string of specified length

4 capitalize()

Returns a copy of the string with only the first character capitalized

5 title()

Returns the element-wise title cased version of the string or unicode

6 lower()

Returns an array with the elements converted to lowercase

7 upper()

Returns an array with the elements converted to uppercase

8 split()

Returns a list of the words in the string, using separatordelimiter

9 splitlines()

Returns a list of the lines in the element, breaking at the line boundaries

10 strip()

Returns a copy with the leading and trailing characters removed

11 join()

Returns a string which is the concatenation of the strings in the sequence

12 replace()

Returns a copy of the string with all occurrences of substring replaced by the new string

13 decode()

Calls str.decode element-wise

14 encode()

Calls str.encode element-wise

These functions are defined in character array class (numpy.char). The older Numarray package contained chararray class. The above functions in numpy.char class are useful in performing vectorized string operations.