Pandas me Data Load aur Explore Karna

Lesson 8 of 26

Real projects me data CSV, Excel ya database se aata hai. Is lesson me hum ek chhota sales dataset load karenge aur usko explore karne ke standard steps seekhenge. Yahi steps aap har naye dataset pe karenge.

CSV load karna

Normally aap pd.read_csv("sales.csv") likhenge. Yaha example ko self-contained rakhne ke liye CSV text ko StringIO se padh rahe hain — result bilkul same hai:

Example

Python
from io import StringIO
import pandas as pd

csv_data = """order_id,date,city,category,product,quantity,price
1001,2026-01-05,Delhi,Electronics,Headphones,2,1500
1002,2026-01-06,Mumbai,Clothing,T-Shirt,3,499
1003,2026-01-06,Delhi,Clothing,Jeans,1,1299
1004,2026-01-07,Bangalore,Electronics,Mouse,4,650
1005,2026-01-08,Mumbai,Grocery,Rice 5kg,2,420
1006,2026-01-09,Pune,Electronics,Keyboard,1,
1007,2026-01-10,Delhi,Grocery,Tea 1kg,5,380
1008,2026-01-11,Bangalore,Clothing,Jacket,1,2499
1009,2026-01-12,Pune,Grocery,Oil 1L,3,160
1010,2026-01-12,Mumbai,Electronics,Charger,2,899"""

df = pd.read_csv(StringIO(csv_data), parse_dates=["date"])

parse_dates=["date"] se date column text ki jagah asli date type ban jaata hai.

head() aur tail()

Example

Python
print(df.head())      # pehli 5 rows
print()
print(df.tail(3))     # aakhri 3 rows

Output

Plain Text
   order_id       date       city     category     product  quantity   price
0      1001 2026-01-05      Delhi  Electronics  Headphones         2  1500.0
1      1002 2026-01-06     Mumbai     Clothing     T-Shirt         3   499.0
2      1003 2026-01-06      Delhi     Clothing       Jeans         1  1299.0
3      1004 2026-01-07  Bangalore  Electronics       Mouse         4   650.0
4      1005 2026-01-08     Mumbai      Grocery    Rice 5kg         2   420.0

   order_id       date       city     category  product  quantity   price
7      1008 2026-01-11  Bangalore     Clothing   Jacket         1  2499.0
8      1009 2026-01-12       Pune      Grocery   Oil 1L         3   160.0
9      1010 2026-01-12     Mumbai  Electronics  Charger         2   899.0

shape aur info()

info() ek hi baar me columns, unke types aur non-null count dikha deta hai. Missing values pakadne ka ye sabse fast tareeka hai:

Example

Python
print(df.shape)
print()
df.info()

Output

Plain Text
(10, 7)

<class 'pandas.core.frame.DataFrame'>
RangeIndex: 10 entries, 0 to 9
Data columns (total 7 columns):
 #   Column    Non-Null Count  Dtype
---  ------    --------------  -----
 0   order_id  10 non-null     int64
 1   date      10 non-null     datetime64[ns]
 2   city      10 non-null     object
 3   category  10 non-null     object
 4   product   10 non-null     object
 5   quantity  10 non-null     int64
 6   price     9 non-null      float64
dtypes: datetime64[ns](1), float64(1), int64(2), object(3)
memory usage: 692.0+ bytes

Dhyan dijiye — price me 10 me se sirf 9 non-null values hain. Yaani ek value missing hai. Isko hum cleaning wale lesson me theek karenge.

describe() — numbers ka summary

Example

Python
print(df[["quantity", "price"]].describe())

Output

Plain Text
        quantity        price
count  10.000000     9.000000
mean    2.400000   922.888889
std     1.349897   736.799573
min     1.000000   160.000000
25%     1.250000   420.000000
50%     2.000000   650.000000
75%     3.000000  1299.000000
max     5.000000  2499.000000

Ek line me count, mean, standard deviation, min, max aur percentiles mil gaye. 50% wali row median hai.

Categories explore karna

Example

Python
print(df["city"].value_counts())
print()
print("Categories:", df["category"].unique())
print("Kitne products:", df["product"].nunique())

Output

Plain Text
city
Delhi        3
Mumbai       3
Bangalore    2
Pune         2
Name: count, dtype: int64

Categories: ['Electronics' 'Clothing' 'Grocery']
Kitne products: 10

Missing values aur sorting

Example

Python
print(df.isnull().sum())
print()
print(df.sort_values("price", ascending=False).head(3))

Output

Plain Text
order_id    0
date        0
city        0
category    0
product     0
quantity    0
price       1
dtype: int64

   order_id       date       city     category     product  quantity   price
7      1008 2026-01-11  Bangalore     Clothing      Jacket         1  2499.0
0      1001 2026-01-05      Delhi  Electronics  Headphones         2  1500.0
2      1003 2026-01-06      Delhi     Clothing       Jeans         1  1299.0

Doosre formats

Source

Padhna

Likhna

CSV

pd.read_csv("file.csv")

df.to_csv("out.csv", index=False)

Excel

pd.read_excel("file.xlsx")

df.to_excel("out.xlsx", index=False)

SQL database

pd.read_sql(query, connection)

df.to_sql("table", connection)

JSON

pd.read_json("file.json")

df.to_json("out.json")

Naya dataset milte hi ye 5 commands chalaiye: head(), shape, info(), describe(), isnull().sum(). Paanch minute me aapko dataset ki poori tasveer mil jaayegi.