numpy string operations | index() function Last Updated : 23 Jan, 2019 Comments Improve Suggest changes Like Article Like Report numpy.core.defchararray.index(arr, sub, start=0, end=None) is another function for doing string operations in numpy. It returns the lowest index in the string where substring sub is found for each element in arr. It returns value error if sub is not contained within the range [start, end]. Parameters: arr : array_like of str or unicode. sub : [str or unicode] The substring which to be searched. start : [ int, optional] The starting location in each string. end : [ int, optional] The ending location in each string. Returns : [ndarray] Output array of int. Code #1 : Python3 # Python program explaining # numpy.char.index() method # importing numpy import numpy as geek # input arrays in_arr = geek.array(['aAaAaA', 'baA', 'abBABba']) print ("Input array : ", in_arr) # output arrays out_arr = geek.char.index(in_arr, sub ='a') print ("Output array: ", out_arr) Output: Input array : ['aAaAaA' 'baA' 'abBABba'] Output array: [0 1 0] Code #2 : Python3 # Python program explaining # numpy.char.index() method # importing numpy import numpy as geek # input arrays in_arr = geek.array(['aAaAaA', 'aA', 'abBABba']) print ("Input array : ", in_arr) # output arrays out_arr = geek.char.index(in_arr, sub ='A', start = 1, end = 4) print ("Output array: ", out_arr) Output: Input array : ['aAaAaA' 'aA' 'abBABba'] Output array: [1 1 3] Code #3 : If substring is not found, raise ValueError. Python3 # Python program explaining # numpy.char.index() method # importing numpy import numpy as geek # input arrays in_arr = geek.array(['aAaAaA', 'aA', 'abBABba']) print ("Input array : ", in_arr) # output arrays out_arr = geek.char.index(in_arr, sub ='A', start = 3, end = 7) print ("Output array: ", out_arr) Output: ValueError: substring not found Comment More infoAdvertise with us Next Article numpy string operations | index() function jana_sayantan Follow Improve Article Tags : Python Python-numpy Python numpy-String Operation Practice Tags : python Similar Reads Numpy - String Functions & Operations NumPy String functions belong to the numpy.char module and are designed to perform element-wise operations on arrays. These functions can help to handle and manipulate string data efficiently.Table of ContentString OperationsString Information String Comparison In this article, we’ll explore the var 5 min read numpy string operations | istitle() function numpy.core.defchararray.istitle(arr) function returns True for each element in the array if the element is a titlecased string and there is at least one character, it returns false otherwise. Parameters: arr : array_like of str or unicode Returns : [ndarray] Output array of bools. Code #1: Python3 # 1 min read numpy string operations | isnumeric() function numpy.core.defchararray.isnumeric(arr) function returns true for each element if there are only numeric characters and there is at least one character.It returns false otherwise. Parameters: arr : array_like of str or unicode. Returns : [ndarray] Output array of bools. Code #1 : Python3 # Python pro 1 min read numpy string operations | lower() function numpy.core.defchararray.lower(arr) function is used to return an array with the elements converted to lowercase. Parameters: arr : [ array_like ] Input array which may be str or unicode. Returns : [ndarray] Output lowercased array of str or unicode, depending on input type. Code #1: Python3 # Python 1 min read numpy string operations | isalpha() function numpy.core.defchararray.isalpha(arr) function returns True for each element if all characters in the string are alphabetic and there is at least one character; returns false otherwise. Parameters: arr : array_like of str or unicode. Returns : [ndarray] Output array of bools. Code #1 : Python3 # Pyth 1 min read numpy string operations | find() function numpy.core.defchararray.find(arr, sub, start=0, end=None) is another function for doing string operations in numpy.It returns the lowest index in the string where substring sub is found for each element in arr within the range start to end.It returns -1 otherwise. Parameters: arr : array_like of str 2 min read numpy string operations | rfind() function numpy.core.defchararray.find(arr, sub, start=0, end=None) is another function for doing string operations in numpy.It returns the highest index in the string where substring sub is found for each element in arr.It returns -1 if sub is not contained within [start, end]. Parameters: arr : array_like o 2 min read numpy string operations | title() function numpy.core.defchararray.title(arr): function is used to Return element-wise title cased version of string or unicode.Title case words start with uppercase characters, all remaining cased characters are lowercase. Parameters: arr : [ array_like ] Input array which may be str or unicode. Returns : [nd 1 min read numpy string operations | zfill() function numpy.core.defchararray.zfill(arr, width) is another function for doing string operations in numpy. For each element in the array it returns the numeric string left-filled with zeros.The number of left filled zeros happen according to the width. Parameters: arr : array_like of str or unicode.Input a 2 min read numpy string operations | count() function numpy.core.defchararray.count(arr, sub, start=0, end=None) is another function for doing string operations in numpy.It returns an array with the number of non-overlapping occurrences of substring sub in the range start to end. Parameters: arr : array_like of str or unicode. sub : [str or unicode] Th 2 min read Like