字符串格式化#

介绍#

Python 中的 .format() 方法用于创建包含变量、表达式或值的字符串。此方法将字符串中的花括号占位符 {} 替换为 .format()中提供的值。

def main():
    x = 1
    y = 5

    # Display the variables using .format()
    console.print("Position: ({}, {})".format(x, y))

# Start threads — Do not delete
start_thread(main)


def main():
    # Display a calculation using .format()
    console.print("Sum: {}".format(5 + 3))

# Start threads — Do not delete
start_thread(main)


def main():
    wait(1, SECONDS)
    # Display the time using .format()
    console.print("Time: {}".format(timer.time(SECONDS)))

# Start threads — Do not delete
start_thread(main)

使用 .format 格式化数字 - 将值和表达式插入字符串。

  • :.xf – Sets the number of decimal places to show.

  • round – Rounds a number to a given number of decimal places.

  • :, – Adds commas as thousands separators.

  • :.x% – Converts a decimal to a percentage with x decimal places.

  • :#x – Formats a number as hexadecimal.

  • :b – Formats a number as binary.

组合字符串——组合文本和值。

  • .format() – Combine strings and variables in a single expression.

  • + operator – Concatenate strings manually with optional type conversion.

字符串方法——更改文本的大小写。

  • upper() – Converts all characters to uppercase.

  • lower() – Converts all characters to lowercase.

检查子字符串——测试文本的存在或位置。

  • in – Checks if a word exists in a string.

  • startswith() – Checks if a string begins with a given value.

  • endswith() – Checks if a string ends with a given value.

转义序列——使用特殊字符格式化输出。

  • \n – Adds a line break (new line).

  • \t – Adds a tab space between items.

使用 .format格式化数字#

.format 可用于控制数字的显示方式，包括小数位、舍入和其他格式样式，例如：

Fixed Decimal Places#

.xf 控制数字显示的小数位数。

用法：
.xf

参数

描述

x

要显示的小数位数。

 
def main():
    # Display pi with 2 decimal places
    pi = 3.1415926535
    console.print("Pi: {:.2f}".format(pi))
    # Output: Pi: 3.14

# Start threads — Do not delete
start_thread(main)

Rounding Numbers#

round 在格式化之前将数字四舍五入到特定的小数位数。

用法：
round(number, x)

参数

描述

number

要舍入的数字。

x

要四舍五入的小数位数。

 
def main():
    # Display a value rounded to only 2 decimal places
    value = 5.6789
    console.print("Rounded: {}".format(round(value, 2)))
    # Output: Rounded: 5.68

# Start threads — Do not delete
start_thread(main)

Thousands Separator#

:, 插入逗号作为千位分隔符，使大数字更易读。

用法：
:,

参数

描述

此格式说明符没有参数。

 
def main():
    # Display a large number separated with commas
    number = 1234567
    console.print("Formatted: ")
    console.new_line()
    console.print("{:,}".format(number))
    # Output: Formatted: 1,234,567

# Start threads — Do not delete
start_thread(main)

Percentage#

:.x% 将小数值格式化为百分比。

用法：
:.x%

参数

描述

x

要显示的小数位数。

 
def main():
    # Display a converted decimal to a percentage
    value = 0.875
    console.print("Score: {:.1%}".format(value))
    # Output: Score: 87.5%

# Start threads — Do not delete
start_thread(main)

Hexadecimal#

:#x 将数字转换为十六进制。

用法：
:#x

参数

描述

此格式说明符没有参数。

 
def main():
    # Convert 255 to hexadecimal
    number = 255
    console.print("Hex: {:#x}".format(number))
    # Output: Hex: 0xff

# Start threads — Do not delete
start_thread(main)

Binary#

:b 将数字转换为二进制（基数 2）。

用法：
:b

参数

描述

此格式说明符没有参数。

 
def main():
    # Convert 3 to binary
    console.print("Binary: {:b}".format(3))
    # Output: Binary: 11

# Start threads — Do not delete
start_thread(main)

组合字符串#

您可以使用两种方法来组合（或连接）字符串：

Using .format#

使用 {}将值直接插入字符串中。

def main():
    # Display an answer based on the given emotion
    emotion = "good"
    console.print("I'm {}, you?".format(emotion))

# Start threads — Do not delete
start_thread(main)

+ Operator#

使用 +连接多个部分。

**注意：**必须首先使用 str()将非字符串转换为字符串。

def main():
    # Display the x and y values
    x = 10
    y = 20
    console.print("X: " + str(x) + ", Y: " + str(y))

# Start threads — Do not delete
start_thread(main)

字符串方法#

Python 提供了修改和检查字符串的内置方法。

upper#

upper 将字符串中的所有字母转换为大写。

用法：
upper()

参数

描述

该方法没有参数。

 
def main():
    # Capitalize a string with .upper()
    message = "vexcode"
    console.print(message.upper())  # Output: VEXCODE

# Start threads — Do not delete
start_thread(main)

lower#

lower 将字符串中的所有字母转换为小写。

用法：
lower()

参数

描述

该方法没有参数。

 
def main():
    # Make a string lowercase with .lower()
    message = "VEXCODE"
    console.print(message.lower())  # Output: vexcode

# Start threads — Do not delete
start_thread(main)

检查子字符串#

in#

in 是一个关键字，它返回一个布尔值，指示字符串中是否存在某个单词。

  • True – The word exists in the string.

  • False – The word does not exist in the string.

def main():
    message = "Hey everyone!"
    if "Hey" in message:
        console.print("Hello!")

# Start threads — Do not delete
start_thread(main)

startswith#

startswith 返回一个布尔值，指示字符串是否以给定值开头。

  • True – The word starts the string.

  • False – The word does not start the string.

用法：
startswith(substring)

参数

描述

substring

要在字符串内检查的子字符串。

 
def main():
    # Check for 'GO' at the start of a string
    message = "GO Robot"

    if message.startswith("GO"):
        console.print("GO first!")

# Start threads — Do not delete
start_thread(main)

endswith#

endswith 返回一个布尔值，指示字符串是否以给定值结尾。

  • True – The word ends the string.

  • False – The word does not end the string.

Usage:
endswith(substring)

参数

描述

substring

要在字符串内检查的子字符串。

 
def main():
    # Check for `Robot` at the end of a string
    message = "GO Robot"

    if message.endswith("Robot"):
        console.print("Robot last!")

# Start threads — Do not delete
start_thread(main)

转义序列#

转义序列是字符串内部用来格式化文本输出的特殊字符。

New Line#

\n 打印时将文本移动到新行。

def main():
    # Display text on two lines
    console.print("First line\nSecond line")

# Start threads — Do not delete
start_thread(main)

Tab Spacing#

\t inserts a tab space between words or numbers.

def main():
    # Display the quantity of disks
    quantity = 2
    console.print("Disks:\t", quantity)

# Start threads — Do not delete
start_thread(main)
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