tryParse 静态方法

将 source 解析为一个可能的带符号整数文常量，并返回其值。

与 parse 相同， except that this method returns null if the input is not valid

示例

print(BigInt.tryParse('-12345678901234567890')); // -12345678901234567890
print(BigInt.tryParse('0xFF')); // 255
print(BigInt.tryParse('0xffffffffffffffff')); // 18446744073709551615

// From binary (base 2) value.
print(BigInt.tryParse('1100', radix: 2)); // 12
print(BigInt.tryParse('00011111', radix: 2)); // 31
print(BigInt.tryParse('011111100101', radix: 2)); // 2021
// From octal (base 8) value.
print(BigInt.tryParse('14', radix: 8)); // 12
print(BigInt.tryParse('37', radix: 8)); // 31
print(BigInt.tryParse('3745', radix: 8)); // 2021
// From hexadecimal (base 16) value.
print(BigInt.tryParse('c', radix: 16)); // 12
print(BigInt.tryParse('1f', radix: 16)); // 31
print(BigInt.tryParse('7e5', radix: 16)); // 2021
// From base 35 value.
print(BigInt.tryParse('y1', radix: 35)); // 1191 == 34 * 35 + 1
print(BigInt.tryParse('z1', radix: 35)); // null
// From base 36 value.
print(BigInt.tryParse('y1', radix: 36)); // 1225 == 34 * 36 + 1
print(BigInt.tryParse('z1', radix: 36)); // 1261 == 35 * 36 + 1