Python3 lstrip() Method

Python3 Strings

Description

The lstrip() method is used to truncate spaces or specified characters on the left side of a string.

Syntax

lstrip() method syntax:

str.lstrip([chars])

Parameters

chars (optional):Specifies a set of characters to be removed (in string form).

If omitted or None, whitespace characters are removed by default (space, \t, \n, \r, \v, \f).

Note:chars is a set of characters, not a complete prefix. The method removes all characters appearing in chars from the left side until it encounters a character not in the set.

Return Value

Returns a new string (the original string is not modified).

Key Features

Only affects the left side: does not affect characters on the right side or in the middle of the string.

Character set matching: chars is a set of characters, not a complete prefix. For example:

"abc123".lstrip("ab")  # 移除 'a' 和 'b' → "c123"

Whitespace character range: includes space, tab (\t), newline (\n), etc.

Comparison with Other Methods

Examples

The following examples demonstrate how to use lstrip():

1. Remove left-side whitespace characters

text = "   Hello, World!   "
result = text.lstrip()
print(result)  # 输出: "Hello, World!   "（右侧空格保留）

2. Remove specified characters from the left side

text = "www.example.com"
result = text.lstrip("wcmo.")  # 移除左侧出现的任意字符：w, c, m, o, .
print(result)  # 输出: "example.com"（左侧的 "www." 被移除）

3. Order of character set is irrelevant

text = "123abc"
result = text.lstrip("321")  # 移除左侧的 '1', '2', '3'（顺序不影响）
print(result)  # 输出: "abc"

4. Stops when encountering a character not in the set

text = "123abc"
result = text.lstrip("12")  # 只移除左侧的 '1' 和 '2'，遇到 '3' 停止
print(result)  # 输出: "3abc"

5. The original string remains unchanged

text = "   Hello"
result = text.lstrip()
print(text)   # 输出: "   Hello"（原字符串未修改）
print(result) # 输出: "Hello"

Python3 Strings