你的担心是多余的

@kidswong999 :你好，我在python编译器里都是直接使用format()函数的，请问在openmv里需要导入哪个库才能解决呢，之前在文档里找没找到

import sensor, image, time,math,pyb
from pyb import UART,LED
import json



red_threshold   = (16, 40, 21, 53, 47, 17)

sensor.reset() 
sensor.set_pixformat(sensor.RGB565) 
sensor.set_framesize(sensor.QQVGA) 
sensor.skip_frames(10) 
sensor.set_auto_whitebal(False) 
clock = time.clock() 


uart = UART(3,115200)   
uart.init(115200, bits=8, parity=None, stop=1) # init with given parameters


K=2554
def Tablefun(list):
    list_set = set(list)  
    frequency_dict = {}
    for i in list_set:  
        frequency_dict[i] = list.count(i)  
    grade_mode = []
    for key, value in frequency_dict.items():  
        if value == max(frequency_dict.values()):
            grade_mode.append(key)
            break
    return grade_mode



while(True):
    Tab_distance=[]
    while(len(Tab_distance)<20):
        length=0
        clock.tick() 
        img = sensor.snapshot() 
        blobs = img.find_blobs([red_threshold])


        if len(blobs) == 1:
            b = blobs[0]
            img.draw_rectangle(b[0:4]) # rect
            img.draw_cross(b[5], b[6]) # cx, cy
            Lm = (b[2]+b[3])/2
            length = K/Lm
            Tab_distance.append(int(length))


    length = Tablefun(Tab_distance)
    # uart.writechar(int(length[0]))
        
    length = format(length[0],'0>3')+ "\r\n"
    uart.write(length)
   
    print(">>", length, "<<")