python手写简易进度条

（2023.9.4）更新：

• 计时、估计剩余时间（ETA，Expected Time of Arrival）；
• 支持手写的、无实现 __len__ 的 generator；
• 支持嵌套使用。

代码见 iTomxy/ml-template/utils/misc.py/prog_bar。例程：

# import time
# from utils import prog_bar

# 训练数据
X = ([1, 2], [3, 4], [5, 6], [7, 8])

# 手写 generator，无 `__len__` 也能用
def _generator(_X):
    for _x in _X:
        yield _x

print("before prog_bar")
# 嵌套循环，嵌套用 prog_bar 只打印最内层的 progress bar
for epoch in prog_bar("abc", "Epoch"): # string
    print('Epoch:', epoch)

    for i in prog_bar(range(15, 7, -2), "range"): # range
        print("\trange:", i)
        time.sleep(0.5)

        for x in prog_bar(X, "X"): # 数据
            print("\t\tX:", x)
            time.sleep(0.2)

    for x in prog_bar(_generator(X), "iterator"): # generator
        print("\titerator:", x)
        time.sleep(1)

print("after prog_bar:")

---

类似 tqdm^[1] 的东西，效果：

• 打印 [ <NOW> / <TOTAL> ] 式简易进度条。支持自定义前缀信息，形如：<MESSAGE>: [ <NOW> / <TOTAL> ]；
• 用法类似 tqdm，可套在 range、list、tuple、numpy.ndarray 上面用 for 遍历。手写的 generator 会报错：TypeError: object of type 'generator' has no len()，不支持，但 tqdm 支持。

原理就是不换行、并用 \r 重写行。

Code & Example

import time
import numpy as np
from collections.abc import Iterable


def prog_bar(iter_obj, prefix=None):
    """simple progress bar (better NOT to use `print` inside)
    Input:
        - iter_obj: iter_obj: range, tuple, list, numpy.ndarray
        - prefix: str, some message to show
    Ref:
        - https://stackoverflow.com/questions/3002085/how-to-print-out-status-bar-and-percentage
    """
    if isinstance(iter_obj, range):
        _start, _stop, _step = iter_obj.start, iter_obj.stop, iter_obj.step
    elif isinstance(iter_obj, Iterable):
        _start, _stop, _step = 0, len(iter_obj), 1
    else:
        raise NotImplemented

    n_digit = len(str(_stop))
    if prefix != None:
        template = "\r{}: [ %*d / %*d ]".format(prefix)
    else:
        template = "\r[ %*d / %*d ]"

    print("", end="")
    print(template % (n_digit, _start, n_digit, _stop), end="")
    for i, x in enumerate(iter_obj):
        yield x
        print(template % (n_digit, _start + (i + 1) * _step, n_digit, _stop), end="")
    print(template % (n_digit, _stop, n_digit, _stop))#, end="")


print("abcd")
for i in prog_bar(range(12, 103, 10)):
    time.sleep(1)
print("efg")

print("hijk")
for x in prog_bar([1, 2, 3], "list"):
    time.sleep(1)
print("lmn")

print("opq")
for x in prog_bar((4, 5, 6), "tuple"):
    time.sleep(1)
print("rst")

print("uvw")
for x in prog_bar(np.array([[7, 8, 9], [10, 11, 12]]), "np.ndarray"):
    time.sleep(1)
print("xyz")

References

1. tqdm/tqdm
2. How to print out status bar and percentage?
3. Python脚本报错：DeprecationWarning: Using or importing the ABCs from ‘collections’ instead of from ‘collections.abc’ is deprecated since Python 3.3,and in 3.9 it will stop working import pymssql