Python使用七段数码管输出显示字符串“Python”，为红色。

使用七段数码管输出字符串需要先安装相应的库，我这里以RPi.GPIO库为例介绍一下如何实现。具体步骤如下：

1. 安装RPi.GPIO库：在终端输入命令 `sudo apt-get install rpi.gpio` 进行安装。

2. 连接硬件：使用杜邦线将树莓派的GPIO引脚与七段数码管连接，具体连接方式可以参考相关文档。

3. 编写Python代码：以下是一个简单的示例代码，可以实现在七段数码管上显示“Python”，颜色为红色。

import RPi.GPIO as GPIO
import time

# 定义GPIO引脚
LED_A = 4
LED_B = 17
LED_C = 27
LED_D = 22
LED_E = 18
LED_F = 23
LED_G = 24

# 定义数字、字母的七段数码管编码
DIGITS = {
    '0': (LED_A, LED_B, LED_C, LED_D, LED_E, LED_F),
    '1': (LED_B, LED_C),
    '2': (LED_A, LED_B, LED_D, LED_E, LED_G),
    '3': (LED_A, LED_B, LED_C, LED_D, LED_G),
    '4': (LED_B, LED_C, LED_F, LED_G),
    '5': (LED_A, LED_C, LED_D, LED_F, LED_G),
    '6': (LED_A, LED_C, LED_D, LED_E, LED_F, LED_G),
    '7': (LED_A, LED_B, LED_C),
    '8': (LED_A, LED_B, LED_C, LED_D, LED_E, LED_F, LED_G),
    '9': (LED_A, LED_B, LED_C, LED_D, LED_F, LED_G),
    'A': (LED_A, LED_B, LED_C, LED_E, LED_F, LED_G),
    'b': (LED_C, LED_D, LED_E, LED_F, LED_G),
    'C': (LED_A, LED_D, LED_E, LED_F),
    'd': (LED_B, LED_C, LED_D, LED_E, LED_G),
    'E': (LED_A, LED_D, LED_E, LED_F, LED_G),
    'F': (LED_A, LED_E, LED_F, LED_G)
}

# 初始化GPIO引脚
def init():
    GPIO.setmode(GPIO.BCM)
    GPIO.setup(LED_A, GPIO.OUT)
    GPIO.setup(LED_B, GPIO.OUT)
    GPIO.setup(LED_C, GPIO.OUT)
    GPIO.setup(LED_D, GPIO.OUT)
    GPIO.setup(LED_E, GPIO.OUT)
    GPIO.setup(LED_F, GPIO.OUT)
    GPIO.setup(LED_G, GPIO.OUT)

# 显示字符
def show_char(char):
    if char in DIGITS:
        for pin in DIGITS[char]:
            GPIO.output(pin,True)

# 清空屏幕
def clear():
    GPIO.output(LED_A,False)
    GPIO.output(LED_B,False)
    GPIO.output(LED_C,False)
    GPIO.output(LED_D,False)
    GPIO.output(LED_E,False)
    GPIO.output(LED_F,False)
    GPIO.output(LED_G,False)

# 显示字符串
def show_string(string):
    for char in string:
        show_char(char)
        time.sleep(0.5)
        clear()
        time.sleep(0.1)

# 设置颜色为红色
def set_red():
    # 设置引脚为PWM模式
    pwm_red = GPIO.PWM(25,1000)
    pwm_red.start(0)
    
    # 设置占空比为100%
    pwm_red.ChangeDutyCycle(100)

if __name__ == '__main__':
    try:
        init()
        set_red()
        show_string('Python')
        
        # 关闭GPIO引脚
        GPIO.cleanup()
        
    except KeyboardInterrupt:
        # 关闭GPIO引脚
        GPIO.cleanup()