python str 左对齐 python左对齐怎么设置

1. 对齐与填充

# 第一种
s = "zhangsan"
# S.ljust(width[, fillchar]) -> str,第二个参数填充的单字符，默认是空字符
s.ljust(20)  # 左对齐  'zhangsan            '    
s.center(20) # 居中对齐  '      zhangsan      '   
s.rjust(20,'-') # 右对齐'-'填充  '------------zhangsan' 

# 第二种format
format(s,'-<20') # 左对齐,'-'填充  'zhangsan------------'
format(s,"^20") #  居中对齐  '      zhangsan      '
format(2,'=>20') # 右对齐，'='填充  '===================2'

2. 例子：按字典键值最大的长度，格式化键左对齐

d = {"zhangsan":18,"lisi":20,"zhaoliu":19,"www":21,"songjiang":33}

maxLength = max(map(len,d.keys())) # 得到键最大长度

d = {k.ljust(maxLength):v for k,v in d.items()}
print(d) # {'zhangsan ': 18, 'lisi     ': 20, 'zhaoliu  ': 19, 'www      ': 21, 'songjiang': 33}