String Indexing and Slicing

Python tutorial · PySpark.in

String Indexing and Slicing in Python

Strings in Python are indexed, meaning every character has a position starting from 0.

String Indexing

```

s = "PYTHON"

print(s[0]) # P

print(s[1]) # Y

print(s[5]) # N (last character)

```

Negative Indexing

Negative indices allow you to access characters from the end.

```

name = "PYSPARK"

print(name[-1]) # K

print(name[-2]) # R

print(name[-3]) # A

print(name[-4]) # P

print(name[-5]) # S

print(name[-6]) # Y

print(name[-7]) # P

```

What is String Slicing?

String slicing means extracting a part of the string (substring).

Syntax

string[start : end : step]

Meaning:

start → starting index (inclusive)
end → ending index (exclusive)
step → skip count (optional)

Examples

```

name = "Pyspark"

print(name[0]) # P

print(name[0:2]) # Py

```

Negative Indices in Slicing

Negative indices allow slicing from the end.

```

name = "Hello"

print(name[2:-1]) # ll

```

Slicing with Step

The step value decides how many characters to skip.

```

name = "Hello01234"

print(name[0:10:1]) # Hello01234 (no skipping)

print(name[0:10:2]) # Hlo24 (skip 1 each time)

print(name[0:10:3]) # Hl13 (skip 2 each time)

```

Rule:
If step = n, Python skips n-1 characters each time.

Omitting Indices

If you don’t specify start or end, Python fills them automatically.

Expression	Equivalent To	Meaning
name[:4]	name[0:4]	From start to index 3
name[1:]	name[1:len(name)]	From index 1 to end
name[:]	name[0:len(name)]	Whole string

Example:

```

name = "Hello01234"

print(name[:4]) # Hell

print(name[1:]) # ello01234

print(name[:]) # Hello01234

```

Important Notes

Slicing works like range() → end index is excluded.
Negative indices count from the end of the string.
step allows skipping characters.
Omitting start defaults to 0, and omitting end defaults to len(string).

String Indexing and Slicing