How to replace string with dictionary in Python?

Question

How to change the string to result?

string = 'John and Mary are good friends'
d = {'John': 'Sam', 'Mary': 'Ann', 'are': 'are not'}

result = 'Sam and Ann are not good friends'

Thank you.

Answer 1

If keys in dictionary have only one word is possible split, map by get and join back:

a = ' '.join(d.get(x, x) for x in string.split())
print (a)
Sam and Ann are not good friends

If possible multiple words and also is necessary use words boundaries for avoid replace substrings:

import re

string = 'John and Mary are good friends'
d = {'John and': 'Sam with', 'Mary': 'Ann', 'are good': 'are not'}

pat = '|'.join(r"\b{}\b".format(x) for x in d.keys())
a = re.sub(pat, lambda x: d.get(x.group(0)), string)
print (a) 
Sam with Ann are not friends

Answer 2

You can do it like this:

string = 'John and Mary are good friends'
d = {'John': 'Sam', 'Mary': 'Ann', 'are': 'are not'}

result = string

for key, value in d.items():
    result = result.replace(key, value)

print(result)

output:
Sam and Ann are not good friends

Answer 3

1 - Iterate over each word of string.

2 - check if word exists in dictionary keys.

3 - If it does exist append value of that word to result. if it does not, append word to result.

Answer 4

Basic approach:

1. split the long string into a list of words
2. iterate through this list of words; if any word exists as a key in the given dictionary, replace that word with the corresponding value from the dictionary
3. join the list of words together using space

string = 'John and Mary are good friends'
d = {'John': 'Sam', 'Mary': 'Ann', 'are': 'are not'}

s = string.split()
for i, el in enumerate(s):
    if el in d:
        s[i] = d[el]
print(' '.join(s))