Learn Python Coding

✨ A Close Look at a FastAPI Example Application ✨ 📖 Set up an example FastAPI app, add path and query parameters, and handle CRUD operations with Pydantic for clean, validated endpoints. 🏷️ #intermediate #api #web-dev

✨ Quiz: A Close Look at a FastAPI Example Application ✨ 📖 Practice FastAPI basics with path parameters, request bodies, async endpoints, and CORS. Build confidence to design and test simple Python web APIs. 🏷️ #intermediate #api #web-dev

✨ vector database | AI Coding Glossary ✨ 📖 A data system optimized for storing and retrieving embedding vectors. 🏷️ #Python

✨ embedding | AI Coding Glossary ✨ 📖 A learned vector representation that maps discrete items, such as words, sentences, documents, images, or users, into a continuous space. 🏷️ #Python

✨ LlamaIndex | AI Coding Tools ✨ 📖 A high-level framework for building RAG and agentic applications. 🏷️ #Python

from nltk.corpus import stopwords
# nltk.download('stopwords') # Run once
stop_words = set(stopwords.words('english'))
filtered = [w for w in words if not w.lower() in stop_words]

VII. Word Normalization (Stemming & Lemmatization) • Stemming (reduce words to their root form).

from nltk.stem import PorterStemmer
ps = PorterStemmer()
stemmed = ps.stem("running") # 'run'

• Lemmatization (reduce words to their dictionary form).

from nltk.stem import WordNetLemmatizer
# nltk.download('wordnet') # Run once
lemmatizer = WordNetLemmatizer()
lemma = lemmatizer.lemmatize("better", pos="a") # 'good'

VIII. Advanced NLP Analysis (Requires pip install spacy and python -m spacy download en_core_web_sm) • Part-of-Speech (POS) Tagging.

import spacy
nlp = spacy.load("en_core_web_sm")
doc = nlp("Apple is looking at buying a U.K. startup.")
for token in doc: print(token.text, token.pos_)

• Named Entity Recognition (NER).

for ent in doc.ents:
    print(ent.text, ent.label_) # Apple ORG, U.K. GPE

• Get word frequency distribution.

from nltk.probability import FreqDist
fdist = FreqDist(word_tokenize("this is a test this is only a test"))

IX. Text Formatting & Encoding • Format strings with f-strings.

name = "Alice"
age = 30
message = f"Name: {name}, Age: {age}"

• Pad a string with leading zeros.

number = "42".zfill(5) # '00042'

• Encode a string to bytes.

byte_string = "hello".encode('utf-8')

• Decode bytes to a string.

original_string = byte_string.decode('utf-8')

X. Text Vectorization (Requires pip install scikit-learn) • Create a Bag-of-Words (BoW) model.

from sklearn.feature_extraction.text import CountVectorizer
corpus = ["This is the first document.", "This is the second document."]
vectorizer = CountVectorizer()
X = vectorizer.fit_transform(corpus)

• Get feature names (the vocabulary).

print(vectorizer.get_feature_names_out())

• Create a TF-IDF model.

from sklearn.feature_extraction.text import TfidfVectorizer
tfidf_vectorizer = TfidfVectorizer()
tfidf_matrix = tfidf_vectorizer.fit_transform(corpus)

XI. More String Utilities • Center a string within a width.

centered = "Hello".center(20, '-') # '-------Hello--------'

• Check if a string is in title case.

"This Is A Title".istitle() # True

• Find the highest index of a substring.

"test test".rfind("test") # Returns 5

• Split from the right.

"path/to/file.txt".rsplit('/', 1) # ['path/to', 'file.txt']

• Create a character translation table.

table = str.maketrans('aeiou', '12345')
vowels_to_num = "hello".translate(table) # 'h2ll4'

• Remove a specific prefix.

"TestCase".removeprefix("Test") # 'Case'

• Remove a specific suffix.

"filename.txt".removesuffix(".txt") # 'filename'

• Check for unicode decimal characters.

"½".isdecimal() # False
"123".isdecimal() # True

• Check for unicode numeric characters.

"½".isnumeric() # True
"²".isnumeric() # True

#Python #TextProcessing #NLP #RegEx #NLTK ━━━━━━━━━━━━━━━ By: @DataScience4 ✨

💡 Top 50 Operations for Text Processing in Python I. Case & Whitespace Manipulation • Convert to lowercase.

text = "Hello World"
lower_text = text.lower()

• Convert to uppercase.

upper_text = text.upper()

• Capitalize the first letter of the string.

capitalized = "hello world".capitalize()

• Convert to title case (each word starts with a capital).

title_text = "hello world".title()

• Swap character case.

swapped = "Hello World".swapcase()

• Remove leading and trailing whitespace.

padded_text = "  hello  "
stripped_text = padded_text.strip()

• Remove leading whitespace.

left_stripped = padded_text.lstrip()

• Remove trailing whitespace.

right_stripped = padded_text.rstrip()

II. Searching, Replacing & Counting • Find the first index of a substring.

index = "hello world".find("world") # Returns 6

• Check if a string starts with a substring.

starts_with_hello = text.startswith("Hello") # True

• Check if a string ends with a substring.

ends_with_world = text.endswith("World") # True

• Replace a substring with another.

new_text = text.replace("World", "Python")

• Count occurrences of a substring.

count = "hello hello".count("hello") # Returns 2

III. Splitting & Joining • Split a string into a list of words.

words = text.split(' ') # ['Hello', 'World']

• Join a list of strings into a single string.

word_list = ["Hello", "Python"]
joined_text = " ".join(word_list)

• Split a string into lines.

multiline = "line one\nline two"
lines = multiline.splitlines()

• Partition a string at the first occurrence of a separator.

parts = "user@domain.com".partition('@') # ('user', '@', 'domain.com')

IV. Character & String Checks • Check if all characters are alphabetic.

"HelloWorld".isalpha() # True

• Check if all characters are digits.

"12345".isdigit() # True

• Check if all characters are alphanumeric.

"Python3".isalnum() # True

• Check if all characters are whitespace.

"  \t\n".isspace() # True

V. Regular Expressions (re module) • Find the first match of a pattern.

import re
match = re.search(r'\d+', 'There are 10 apples.')

• Find all matches of a pattern.

numbers = re.findall(r'\d+', '10 apples and 20 oranges')

• Substitute a pattern with a replacement string.

no_digits = re.sub(r'\d', '#', 'My pin is 1234')

• Split a string by a regex pattern.

items = re.split(r'[,;]', 'apple,banana;cherry')

VI. Basic NLP - Tokenization & Cleaning (Requires pip install nltk) • Sentence Tokenization.

from nltk.tokenize import sent_tokenize
# nltk.download('punkt') # Run once
text = "Hello Mr. Smith. How are you?"
sentences = sent_tokenize(text)

• Word Tokenization.

from nltk.tokenize import word_tokenize
words = word_tokenize("Hello, how are you?")

• Remove punctuation.

import string
text = "A string with... punctuation!"
clean = text.translate(str.maketrans('', '', string.punctuation))

• Remove stop words.

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