python - Argparse库使用报错too few arguments

问题描述

from PIL import Imageimport argparseparser=argparse.ArgumentParser()parser.add_argument(’IMG_20170430_130454.jpg’)parser.add_argument(’-o’,’--output’)parser.add_argument(’--width’,type=int,default=80)parser.add_argument(’--height’,type=int,default=65)args=parser.parse_args()IMG=args.fileWIDTH=args.widthHEIGHT=args.heightOUTPUT=args.outputascii_char=list('I lve you')def get_char(r,g,b,alpha=256): if alpha==0:return ’ ’ length=len(ascii_char) gray=int(0.2126*r+0.7152*g+0.0722*b) unit=(256.0+1)/length return ascii_char[int(gray/unit)]if __name__==’__main__’: im=Image.open(IMG) im=im.resize((WIDTH,HEIGHT),Image.NEAREST) txt='' for i in range(HEIGHT):for j in range((WIDTH)): txt+=get_char(*im.getpixe((j,i)))txt+=’n’ if OUTPUT:with open(OUTPUT,’w’) as f: f.write(txt) else:with open('output.txt',’w’) as f: f.write(txt)

我运行时候报错usage: ascii.py [-h] [-o OUTPUT] [--width WIDTH] [--height HEIGHT]

IMG_20170430_130454.jpg

ascii.py: error: too few arguments

问题解答

第一个参数缺少参数名

parser.add_argument(’--file’, default=’IMG_20170430_130454.jpg’)