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"""
Operations on strings:
- calculate distance between two strings
- transform strings with transformation codes
"""
#### Ngrams
def getNgrams (sWord, n=2):
"return a list of Ngrams strings"
return [ sWord[i:i+n] for i in range(len(sWord)-n+1) ]
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"""
Operations on strings:
- calculate distance between two strings
- transform strings with transformation codes
"""
from .char_player import distanceBetweenChars
#### Ngrams
def getNgrams (sWord, n=2):
"return a list of Ngrams strings"
return [ sWord[i:i+n] for i in range(len(sWord)-n+1) ]
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nLen2 = len(s2)
for i in range(-1, nLen1+1):
d[i, -1] = i + 1
for j in range(-1, nLen2+1):
d[-1, j] = j + 1
for i in range(nLen1):
for j in range(nLen2):
nCost = 0 if s1[i] == s2[j] else 1
d[i, j] = min(
d[i-1, j] + 1, # Deletion
d[i, j-1] + 1, # Insertion
d[i-1, j-1] + nCost, # Substitution
)
if i and j and s1[i] == s2[j-1] and s1[i-1] == s2[j]:
d[i, j] = min(d[i, j], d[i-2, j-2] + nCost) # Transposition
return d[nLen1-1, nLen2-1]
def distanceSift4 (s1, s2, nMaxOffset=5):
"implementation of general Sift4."
# https://siderite.blogspot.com/2014/11/super-fast-and-accurate-string-distance.html
if not s1:
return len(s2)
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nLen2 = len(s2)
for i in range(-1, nLen1+1):
d[i, -1] = i + 1
for j in range(-1, nLen2+1):
d[-1, j] = j + 1
for i in range(nLen1):
for j in range(nLen2):
#nCost = 0 if s1[i] == s2[j] else 1
nCost = distanceBetweenChars(s1[i], s2[j])
d[i, j] = min(
d[i-1, j] + 1, # Deletion
d[i, j-1] + 1, # Insertion
d[i-1, j-1] + nCost, # Substitution
)
if i and j and s1[i] == s2[j-1] and s1[i-1] == s2[j]:
d[i, j] = min(d[i, j], d[i-2, j-2] + nCost) # Transposition
return int(d[nLen1-1, nLen2-1])
def distanceSift4 (s1, s2, nMaxOffset=5):
"implementation of general Sift4."
# https://siderite.blogspot.com/2014/11/super-fast-and-accurate-string-distance.html
if not s1:
return len(s2)
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