String Distance Matrix in Python using pdist

You need to wrap the distance function, like I demonstrated in the following example with the Levensthein distance

import numpy as np    
from Levenshtein import distance
from scipy.spatial.distance import pdist, squareform

# my list of strings
strings = ["hello","hallo","choco"]

# prepare 2 dimensional array M x N (M entries (3) with N dimensions (1)) 
transformed_strings = np.array(strings).reshape(-1,1)

# calculate condensed distance matrix by wrapping the Levenshtein distance function
distance_matrix = pdist(transformed_strings,lambda x,y: distance(x[0],y[0]))

# get square matrix
print(squareform(distance_matrix))

Output:
array([[ 0.,  1.,  4.],
       [ 1.,  0.,  4.],
       [ 4.,  4.,  0.]])