Merge pull request #298 from realpython/replace-string

How to Replace a String

Author: KateFinegan

replace-string-python/README.md

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+# How to Replace a String in Python
+
+These are the code examples from the Real Python tutorial [How to Replace a String in Python](https://realpython.com/replace-string-python/).
+
+Additionally, there are a few extra code samples included here that didn't make it into the tutorial.

replace-string-python/bad_json.py

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+import re
+import json
+
+data = """{
+    birthday = 1991
+    name = Python
+    creator = Guido van Rossum
+}"""
+
+
+def try_decode(data):
+    print("Trying to decode...")
+    try:
+        output = json.loads(data)
+        print("success")
+        return output
+    except json.decoder.JSONDecodeError as e:
+        print("FAIL")
+        print(e)
+
+
+try_decode(data)
+
+
+print(re.sub(pattern=r"(.+)(=)(.+)", repl=r'"\1":"\3"', string=data))
+try_decode(data)
+
+
+data = re.sub(pattern=r"\s+(.+)(\s+=\s+)(.+)", repl=r'"\1":"\3",', string=data)
+print(data)
+try_decode(data)
+
+
+# Remove last comma
+data = re.sub(pattern=r",$", repl="", string=data, flags=re.MULTILINE)
+print(data)
+data = try_decode(data)

replace-string-python/bad_json_callback.py

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+import re
+import json
+
+data = """{
+    birthday = 1991
+    name = Python
+    creator = Guido van Rossum
+}"""
+
+
+def try_decode(data):
+    print("Trying to decode...")
+    try:
+        output = json.loads(data)
+        print("success")
+        return output
+    except json.decoder.JSONDecodeError as e:
+        print("FAIL")
+        print(e)
+
+
+def cleaner(match):
+    return f'"{match.group(1).strip()}":"{match.group(3).strip()}",'
+
+
+data = re.sub(pattern=r"(.+)(=)(.+)", repl=cleaner, string=data)
+print(data)
+
+# Remove last comma
+data = re.sub(pattern=r",(\s)+}", repl="}", string=data, flags=re.MULTILINE)
+print(data)
+
+try_decode(data)

replace-string-python/transcript_basic.py

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+transcript = """
+[support_tom] 2022-08-24T10:02:23+00:00 : What can I help you with?
+[johndoe] 2022-08-24T10:03:15+00:00 : I CAN'T CONNECT TO MY BLASTED ACCOUNT
+[support_tom] 2022-08-24T10:03:30+00:00 : Are you sure it's not your caps lock?
+[johndoe] 2022-08-24T10:04:03+00:00 : Blast! You're right!
+"""
+
+print(transcript.replace("BLASTED", "😤"))
+
+print(transcript.replace("BLASTED", "😤").replace("Blast", "😤"))
+
+replacements = [
+    ("BLASTED", "😤"),
+    ("Blast", "😤"),
+    ("2022-08-24T", ""),
+    ("+00:00", ""),
+    ("[support_tom]", "Agent"),
+    ("[johndoe]", "Client"),
+]
+
+for old, new in replacements:
+    transcript = transcript.replace(old, new)
+
+print(transcript)

replace-string-python/transcript_reduce.py

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+from functools import reduce
+
+transcript = """
+[support_tom] 2022-08-24T10:02:23+00:00 : What can I help you with?
+[johndoe] 2022-08-24T10:03:15+00:00 : I CAN'T CONNECT TO MY BLASTED ACCOUNT
+[support_tom] 2022-08-24T10:03:30+00:00 : Are you sure it's not your caps lock?
+[johndoe] 2022-08-24T10:04:03+00:00 : Blast! You're right!
+"""
+
+replacements = [
+    ("BLASTED", "😤"),
+    ("Blast", "😤"),
+    ("2022-08-24T", ""),
+    ("+00:00", ""),
+    ("[support_tom]", "Tom"),
+    ("[johndoe]", "Client"),
+]
+
+print(reduce(lambda acc, item: acc.replace(*item), replacements, transcript))

replace-string-python/transcript_regex.py

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+import re
+
+transcript = """
+[support_tom] 2022-08-24T10:02:23+00:00 : What can I help you with?
+[johndoe] 2022-08-24T10:03:15+00:00 : I CAN'T CONNECT TO MY BLASTED ACCOUNT
+[support_tom] 2022-08-24T10:03:30+00:00 : Are you sure it's not your caps lock?
+[johndoe] 2022-08-24T10:04:03+00:00 : Blast! You're right!
+"""
+
+regex_replacements = [
+    (r"blast\w*", "😤"),
+    (r" [-T:\+\d]{25}", ""),
+    (r"\[support\w*\]", "Agent"),
+    (r"\[johndoe\]", "Client"),
+]
+
+for regex_find, regex_replace in regex_replacements:
+    transcript = re.sub(
+        regex_find, regex_replace, transcript, flags=re.IGNORECASE
+    )
+
+print(transcript)

replace-string-python/transcript_regex_callback.py

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+import re
+
+transcript = """
+[support_tom] 2022-08-24T10:02:23+00:00 : What can I help you with?
+[johndoe] 2022-08-24T10:03:15+00:00 : I CAN'T CONNECT TO MY BLASTED ACCOUNT
+[support_tom] 2022-08-24T10:03:30+00:00 : Are you sure it's not your caps lock?
+[johndoe] 2022-08-24T10:04:03+00:00 : Blast! You're right!
+"""
+
+message_pattern = r"(\[.+\]) ([-T:\+\d]{25}) : (.+)"
+
+BAD_WORDS = ["blast", "dash", "beezlebub"]
+CLIENTS = ["johndoe", "janedoe"]
+
+
+def censor_bad_words(message):
+    for word in BAD_WORDS:
+        message = re.sub(rf"{word}\w*", "😤", message, flags=re.IGNORECASE)
+    return message
+
+
+def censor_clients(user):
+    for client in CLIENTS:
+        user = re.sub(rf"\[{client}\]", "Client", user)
+    return user
+
+
+def sanitize_message(match):
+    user, _, message = match.groups()
+    user = re.sub(r"\[.*support.*\]", "Agent", user)
+    return f"{censor_clients(user)} : {censor_bad_words(message)}"
+
+
+print(re.sub(message_pattern, sanitize_message, transcript))