eval

I want to write a tool in Python to prepare a simulation study by creating for each simulation run a folder and a configuration file with some run-specific parameters. study/ study.conf run1 run.conf run2 run.conf The tool should read the overall study configuration from a file including (1) static parameters (key-value pairs), (2) lists for iteration parameters, and (3) some small code snippets to calculate further parameters from the previous ones. The latter are run specific depending on the permutation of the iteration parameters used. Before writing the run.conf files from a template, I

eval() seems to be dangerous to use when processing unknown strings, which is what a part of my project is doing. For my project I have a string, called: stringAsByte = "b'a'" I've tried to do the following to convert that string directly (without using eval): byteRepresentation = str.encode(stringAsByte) print(byteRepresentation) # prints b"b'a'" Clearly, that didn't work, so instead of doing: byteRepresentation = eval(stringAsByte) # Uses eval! print(byteRepresentation) # prints b'a' Is there another way where I can get the output b'a'? yes, with ast.literal_eval which is safe since it only

1.sys import sys a=eval(sys.argv[1]) b=eval(sys.argv[2]) print(a+b) 1 2 3 4 5 6 evel（）函数是将字符串形式的int，字典等转化成对应真正的int，字典 在这里插入图片描述 2.argparse（python自带库） import argparse parser = argparse.ArgumentParser(description="Demo of argparse") parser.add_argument('-n','--name', default=' 5 ') parser.add_argument('-y','--year', default='20') args = parser.parse_args() print(args) a = args.name b = args.year print(type(a)) print(a+b) 来源： https://www.cnblogs.com/ruiy/p/11730224.html

I have a string returnd from a software like "('mono')" from that I needed to convert string to tuple . that I was thinking using ast.literal_eval("('mono')") but it is saying malformed string. Since you want tuples, you must expect lists of more than element in some cases. Unfortunately you don't give examples beyond the trivial (mono) , so we have to guess. Here's my guess: "(mono)" "(two,elements)" "(even,more,elements)" If all your data looks like this, turn it into a list by splitting the string (minus the surrounding parens), then call the tuple constructor. Works even in the single

Why can a string like "{opacity: 1.0, width: '132px'}" not be evaluated using eval() as is? eval("{opacity: 1.0, width: '132px'}"); // invalid label // {opacity: 1.0, width: '132px'} // ---------------ꜛ eval("v = {opacity: 1.0, width: '132px'}"); // works! Why can a string like "{opacity: 1.0, width: '132px'}" not be evaluated using eval() as is? Because the text occurs where a statement or block is expected, not an expression, and so the { denotes the beginning of a block , not the beginning of an object initializer . (And then opacity: is interpreted as a label followed by the statement

1、字符串 定义：它是一个有序的字符的集合，用于存储和表示基本的文本信息，‘’或“”或‘’‘ ’‘’中间包含的内容称之为字符串特性：1.只能存放一个值2.不可变3.按照从左到右的顺序定义字符集合，下标从0开始顺序访问，有序补充：　　1.字符串的单引号和双引号都无法取消特殊字符的含义，如果想让引号内所有字符均取消特殊意义，在引号前面加r，如name＝r'l\thf'　　2.unicode字符串与r连用必需在r前面，如name＝ur'l\thf' 2、字符串常用操作 # 1字母处理： .upper() # 全部大写 .lower() # 全部小写 .swapcase() # 大小写互换 .capitalize() # 首字母大写，其余小写 .title() # 首字母大写 a='helLO' print(a.upper()) # 全部大写 print(a.lower()) # 全部小写 print(a.swapcase()) # 大小写互换 print(a.capitalize()) # 首字母大写，其余小写 print(a.title()) # 首字母大写 View Code # 2格式化相关 .ljust(width) # 获取固定长度，左对齐，右边不够用空格补齐 .rjust(width) # 获取固定长度，右对齐，左边不够用空格补齐 .center(width) #