[Tut] How to Find the Longest String in a NumPy Array?

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How to Find the Longest String in a NumPy Array?

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Python Longest String in NumPy Array

To find the longest string in a given NumPy array, say

Code:

arr

, you can use the

Code:

max(arr, key=len)

function that determines the maximum by comparing the length of the array elements using the

Code:

len()

function as a key for comparison.

Code:

import numpy as np arr = np.array(['Alice', 'Bob', 'Carl']) print(max(arr, key=len)) # Alice

You can find more about the powerful

Code:

max()

function in our detailed blog tutorial:

Recommended Tutorial: Python Maximum Function

Python Length of Longest String in NumPy Array

To find the length of the longest string in a NumPy array

Code:

arr

, use the

Code:

max(arr, key=len)

function to obtain the string with the maximum length and then pass this max string into the

Code:

len()

function to obtain the number of characters of the max string.

Code:

len(max(arr, key=len))

Here’s a more detailed code example of a simple 1D NumPy Array:

Code:

import numpy as np arr = np.array(['Alice', 'Bob', 'Carl']) # Print Longest String: print(max(arr, key=len)) # Alice # Print Length of Longest String print(len(max(arr, key=len))) # 5

Get Longest String from NumPy Axis (2D, Column or Row)

To get the longest string from a certain NumPy array axis (e.g., row or column), first use simple NumPy slicing and indexing to get that axis (e.g.,

Code:

arr[0, :]

to get the first row) and pass it into the

Code:

max()

function with the

Code:

key

argument set to the length function like so:

Code:

max(arr[0, :], key=len)

.

Here’s an example to get the longest string of the first row of a 2D array:

Code:

import numpy as np arr = np.array([['Alice', 'Bob', 'Carl'], ['Ann', 'Zoe', 'Leonard']]) print(max(arr[0, :], key=len)) # Alice

Here’s an example to get the longest string of the third column of a 2D array:

Code:

print(max(arr[:, 2], key=len)) # Leonard

You get the idea.

If you want to get the longest string from the whole NumPy array, not only from a column or row or axis, first flatten it and then pass the flattened array into the

Code:

max()

function using the

Code:

key=len

argument.

Recommended Tutorial: How to Flatten a NumPy Array?